Russian Journal of Marine Biology

This paper provides a brief review of the biogeographic concepts of the renowned Swedish biogeographer, zoologist, and limnologist Sven Petrus Ekman (1876–1964). He was the author of the first systematized treatise on historical marine biogeography (Ekman, 1935, 1953), in which he formulated the concept of the relict nature of contemporary tropical biotas derived from the Paleogene biota of the Tethys. Ekman (1915, 1920, 1935) proposed a biogeographic definition of the term “relict”: a species (or genus, etc.) is relic to a region if it is isolated here from the main center of distribution and if its presence can only be explained by the fact that either it or its ancestral form were left behind under different environmental conditions than at present.

Without Abstract

The patterns of pigment distribution in the shell of the gastropod Littorina obtusata were studied. It was determined that the background coloration of the periwinkle shell resulted from the coloration interaction of the external and internal parts of the ostracum. The coloration of the latter can be monochromatic or twolayer. The external and/or internal zones of the ostracum can be colored purple, white, orange, yellow and greenish. Only 11 of 25 possible color combinations were recorded. Four additional versions of shell background coloration resulted from partial depigmentation of external or internal parts of ostracum. The mottling pattern corresponded to white or depigmented lenticular sites in the external part of the ostracum. The bands on the shell may be subdivided into two groups according to their means of formation. The bands that appeared due to redistribution of pigments forming background coloration belonged to the first group, the bands arising as a layer of additional (white, yellow, orange) pigment belonged to the second group. Various band versions could occur simultaneously in the same individual.

The netted dog whelk Nassarius reticulatus (Linnaeus, 1758), considered as an extinct benthic species in German Baltic waters, was found again alive in the Mecklenburg Bight during several macrozoobenthic surveys since 1997. All data indicate that the establishment of this marine prosobranch species is connected with the more frequent intrusions of highly saline water from the North Sea into the Baltic that have been observed over the past few years. It is proposed that N. reticulatus is a good bioindicator for the hydrographic status in the western Baltic rather than for other existing potential conditions. Since 1998 a second extinct marine species, the polychaete Scalibregma inflatum Rathke, 1843 was found alive here, too.

Electron-dense germinal granules, which are usually regarded as markers and key organelles of germline cells, were revealed in the interstitial (stem) cells of the colonial hydroids Obelia longissima and Ectopleura crocea. The interstitial cells of O. longissima displayed intense alkaline phosphatase activity, a histochemical marker for vertebrate embryonic stem and primary germ cells, as well as positive reaction to proliferating cell nuclear antigen (PCNA), which is an immunochemical marker for cell reproduction. Our findings and the literature data suggest the evolutionary conservation and similarity of the morphological and functional organization of potentially gametogenic stem cells in asexually reproducing invertebrates and germ cells in all studied Metazoa. The self-renewing pool of such stem cells provides the cellular source for blastogenesis and gametogenesis and the cellular basis for life functions, including both asexual and sexual reproduction. Keywordscolonial hydroids–interstitial cells–germinal granules–germ plasm

The activity and temperature characteristics of hydrolases (maltase, α-amylase, total proteinase, alkaline phosphatase) in the intestine of Far Eastern flatfishes were studied. The character of the temperature dependence differed among the investigated enzymes. The activity of individual hydrolases in the two fish species varied. The results of this study suggest that flatfish intestinal hydrolases are efficient at low temperatures and that the digestive process in flatfishes is well adapted to the conditions in which it functions, thus ensuring optimal vital activity at low temperatures in the Far Eastern seas.

The yellow-lipped sea krait, Laticauda colubrina (Schneider, 1799), is recorded in the waters of Vietnam for the second time. The morphological characteristics of this species are described. Identification keys, a checklist, and distribution data for sea snakes of Vietnam are provided, proceeding from museum collections and extensive analysis of the available literature. Thalassophis anomalus P. Schmidt, 1852 and Leioselasma melanocephala (Gray, 1849) are registered for the first time for Vietnamese waters.

Validation is provided for the establishment of the genus Polyodontognathus for the sea snake Hydrophis caerulescens. The polytypy of this species is demonstrated. The description of the species is improved, and new information is presented about its distribution and osteology.

Information is presented about a finding of two specimens of a rare sea snake Leioselasma czeblukovi, which was known until now only from the holotype and a paratype, and also about the taxonomical position of the genus Leioselasma within the group of genera Hydrophis sensu lato and the species composition of the latter. An identification key for species is presented.

The variability of the Gmo3, Gmo34, Gmo35, and Pgmo32 DNA microsatellite loci in Pacific cod Gadus macrocephalus samples from different areas of the North Pacific was analyzed. The data obtained show that Pacific cod from the southern Kuril Islands significantly differs from the populations of the Bering Sea, the Sea of Okhotsk, and the coastal waters of Canada (the microsatellite loci Gmo3 and Pgmo32 bear the highest differentiating capacity). Despite the significant geographical remoteness of these areas from one another, the above three Pacific cod populations exhibit a high degree of similarity (I = 0.997–0.999).

In Peter the Great Bay, the spotted Seal (Phoca largha) is closely connected with island haulout sites sites all year round and forms four types of onshore associations, preliminary, reproductive, molting, and rehabilitative. It has been found over long term studies that changes in these associations make up an annual cycle. The specific redistribution pattern of seals in the bay appears to be a result of consecutive transformation processes, viz., the break up of previous types of associations and the simultaneous formation of the following ones. The mechanisms underlying every type of onshore associations of spotted seals and the peculiarities of their functioning are discussed. Key wordsspotted seal- Phoca largha -onshore associations-haulout site-Peter the Great Bay-Sea of Japan

The structure of the coating surrounding the metacercaria of Cryptocotyle lingua in the skin and the metacercaria of Liliatrema skrjabini in the muscles of the stone cockscomb was studied. Metacercariae of these trematodes were surrounded by a cyst adjacent to the helminth and by a capsule. In both species, the cyst consisted of electron- dense homogeneous material, which was probably synthesized by the parasite. The capsules were formed from host tissues; in C. lingua, they mostly consisted of ordered layers of collagen fibers and in L. skrjabini they were formed from fibroblasts and, presumably, phagocytes. The differences in capsule structure of the studied metacercariae may be related to the physiological features of surrounding tissues or to the taxonomic attribution of the trematodes.

The stomach contents were examined in 373 walleye pollack larvae of different sizes. The diet of pollack larvae included more than 20 plankters of different sizes. Phytoplankton was the major food source of 4- to 6-mm-long larvae. The proportion of phytoplankton in the larval diet decreased as the larvae grew, and the late larval stages shifted entirely to a diet of zooplankton. As the larvae increased in size, the spectrum of food organisms changed from smaller to larger sizes. In the larvae 4 to 31 mm long, the length of prey varied from 0.1 (Coscinodiscus) to 6.0 mm (Neocalanus plumchrus). The average daily repleteness of pollack larvae varied from 32 to 210. The minimum repleteness was registered in 4- to 6-mm-long larvae with mixed feeding (endogenous and exogenous); in 30- to 35-mm-long fish the repleteness was the greatest. The daily food rations calculated for the most abundant size groups of larvae ranged from 4.3 to 6.6% of their body weight.

Histopathological changes have been revealed associated with shell disease in the red king crab, Paralithodes camtschaticus. The changes in the gills, esophagus, stomach, hepatopancreas, heart, and antennal glands of the crabs are described.

The reproduction and larval development of the sea limpet Lottia persona (Rathke, 1833) were investigated in vitro for the first time. The limpets breed in late July; they have external fertilization and a pelagic lecithotrophic type of development. The larval shell is transparent, symmetrical, and bottle-shaped, with well-pronounced lateral fossae and a large rounded operculum. The protoconch sculpture is characterized by broad wavy lines and radial ribs at the dorsal side. Ventrally, the lines become narrow and are directed perpendicular to those of the dorsal and lateral regions. Development from fertilization to settling lasts 3 days at a water temperature of 19–20°C. Keywordssea limpets–reproduction–egg cell–trochophore–veliger–protoconch

Redescription of a single Russian finding of the erabu seakrait Pseudolaticauda semifasciata is provided and all findings of sea snakes in Russian territory are listed. A key for the identification of sea snakes of the Sea of Japan is provided.

The taxonomic composition of the entire foraminiferan assemblage in the southern part of Peter the Great Bay (Sea of Japan) was studied during the summer 1999 expedition. Along with other foraminiferans, several offspring-filled tests of Planoglabratella opercularis (d'Orbigny, 1839) were found in surface sediment samples. Based on the extensive literature on the reproductive cycle of foraminiferans and indirect evidence, it was found that each of the parent individuals of this species was a partner in a plastogamous pair, thus being a gamont, while their offspring were agamonts. The gamogony stage, contrary to the generally accepted opinion, took place under natural conditions in summer (not in fall or winter) at a bottom water temperature of 15–18C. The results of this research may be important in paleogeographical and paleoecological reconstructions.

The influence of temperature on the duration of infradian (over 28 h) rhythms of reproduction in the green alga Ulva fenestrata was studied in the laboratory under controlled conditions combining four temperatures (5, 10, 15, and 20°C), two irradiance levels (40 and 60 μE/(m2 s)) and neutral daylengths (12: 12 h light: dark). The rise in water temperature explained 78.4% of the reduction in the reproduction cycles (from 30 to 5 days). It is suggested that U. fenestrata has an endogenous reproductive rhythm with a period of 5 days. In unfavorable conditions, one or more reproduction cycles are omitted, and formation of gametes or spores attains a periodicity of 10, 15, or more days. Keywords Ulva –infradian rhythms–reproduction–temperature–irradiance–morphology of reproductive tissue

A bloom in the water of Amursky Bay (Sea of Japan) caused by the dinoflagellate Oxyrrhis marina Dujardin, 1841 was recorded for the first time. The highest density of this species in the bloom area was 443.3 million cells/liter. The abundant development of microalga was observed from July to September 2002 at a water temperature of 17–24.5C and a salinity of 7–18. Changes in the density of O. marina and other species of phytoplankton during the bloom period are analyzed. Possible reasons for the blooms of O. marina in Amursky Bay are discussed.

The process of resorption of spermatozoa is described in the testes of the starfish Asterina pectinifera. It is shown that the mode of resorption of the male gametes in this species is different from that in the starfish Asterias vulgaris (see Walker [17, 18]), A. amurensis, and Aphelasterias japonica (see Kas'yanov et al. [3]). In these species the resorption of nonreleased spermatozoa is performed by auxiliary cells transformed into motile phagocytes. In A. pectinifera this function is performed by coelomocytes migrating into the gonad. The obtained data allow us to reach a conclusion about the presence of different mechanisms of the resorption of nonreleased male gametes in the gonads of sea stars.

Using materials on the euphausiacean Thysanoessa inermis collected in the Norwegian and Barents seas (from 60°N to 73°N) we studied the variability of size characteristics in the eggs (diameter of embryos and egg capsules and the width of the perivitelline space) and their correlations with water temperature and salinity. The size of embryos showed almost no variability irrespective of the location of the sampling site and the water temperature and salinity; the perivitelline space performs a protective function, and its width showed a tendency to decrease with increasing water temperature and salinity. The similarities in the size of embryos in T. inermis populations thousands of kilometers away from each other might be explained, first, by the relatively small age of the populations (the age of the population from the Barents Sea did not exceed 6000–7000 years) and second, by movement of the crustaceans with currents from the Norwegian Sea to the Barents Sea.

According to the results of a comparative analysis of the size and age structures of samples from a population of the bivalve mollusk Ruditapes philippinarum (Manila clam) and from shell assemblages of this species, the possibility of data acquisition on populations using samples from shell assemblages was assessed. A considerable coincidence of these parameters after taking the losses of small individuals during formation of shell assemblage into account, which depended on the location and conditions of assemblage formation, was recorded. Due to the good level of preservation of the shells of older individuals, the sample from the assemblage gave a more comprehensive appreciation of the maximum size and life span of the species than the sample of live mollusks from the natural habitat. Samples from shell assemblages may be used for growth rate estimation of clams without catching live individuals, as the results from studying the linear growth of mollusks based on samples from live populations and from shell assemblages did not differ significantly. Samples from many-year shell accumulations can also be useful for revealing the periods of the highest death rates, the most vulnerable periods in the ontogenesis of the mollusks, and, in some cases, the causes of their death. Keywordsmollusks–population structure–growth–age–shells–Ruditapes philippinarum

Specifics of the digestive cycle were studied in normal individuals of Gray’s mussel Crenomytilus grayanus and in those infested by trematodes from an unpolluted area of the sublittoral zone of Peter the Great Bay in May (during the day), June, July, and August. Four types of tubules corresponding to four phases of the digestive cycle were identified, and three varieties of destructing tubules were distinguished. It was shown that normally phases of absorption and digestion prevailed in the digestive gland. The portion of absorptive tubules (type II) was 95% in spring and 79% in summer. The total portion of destructing and restoring tubules (types III and IV) did not exceed 10% in spring and 20% in summer, and portion of tubules at the initial condition (type I) was 4% in spring and 2% in summer. During the day, insignificant variations in the ratio of different type tubules were recorded. It was revealed that, normally, granulocytomes were formed during utilization of necrotic tubules. Parasitic invasion of trematodes entailed swelling of the gland and a change in the proportion of tubules: the number of absorptive tubules decreased to 20%, the number of destructing and restoring tubules increased up to 60% and 12%, respectively.

The histomorphology of the digestive gland of the bivalve mollusk Crenomytilus grayanus from Sivuchya Bay, which is located in the southwest of Peter the Great Bay and subjected to the effect of polluted waters of Tumannaya River, was studied. Pathological changes of the digestive tubules, channels, and connective tissue of the gland were recorded in all the mussels studied. The epithelium of the tubules and channels was characteristic with erosive disturbances and by heavy vacuolization of digestive cells; connective tissue of the gland was specified by cells with lipofuscin (granulocytomes) and by foci of cells necrosis and lysis. Nervous fibers running in the gland were swollen in some mollusks. Strongly basophilic spherical formations, presumably one of the development stages of a parasitic plasmodium, were found in the granulocytomes and among vesicular cells of connective tissue of all the mussels. It was concluded that pathological changes in digestive gland of Gray’s mussel might be caused by chronic pollution of the bay and by parasitic invasion.

A rare species of the spariform fish Acanthopagrus schlegelii from Russian waters is described. The synonymy of this species and the related literature data are analyzed. It is suggested that two species occur in Russian waters that differ in body coloration: A. schlegelii and A. czerskii.

The pilot mariculture facility for rearing commercial invertebrates has existed in Minonosok Bay of Posyet Bay, Sea of Japan, since 1971. This bay is one of the few in Primorsky Krai where the risk of destruction of mariculture plantations from the effect of storms is a minimum. The total annually yield of spat of the Japanese scallop varied from 6 to 10 million individuals. Two-thirds of this amount was placed in cages for further rearing, and the rest was seeded on the bottom or passed to other enterprises. From 1972 to 2002 there were 104 million individuals of fitted juveniles (yearlings) and 24 million young-of-the-year seeded on the bottom in coastal water areas of the Primorsky Krai from Minonosok Bay. Thanks to the activity of the mariculture farm (two farms since 1994) in Posyet Bay, the stock of the Japanese scallop, which had been depleted by over-fishing in 1934–1935, was completely restored, and, according to our assumption, the total stock of the Japanese scallop was increased two times in Peter the Great Bay.

A new species and genus of scleraxonian octocoral from the South Atlantic is described and illustrated. The specimen is characterized by a medulla highly penetrated with solenia and not separated from the cortex by a boundary of longitudinal canals; therefore, it belongs to the family Briareidae. The material studied differs from the genusBriareum, in which the colonies are unbranched, lobate, or digitate and the distinctive sclerites are triradiate. A key to the family Briareidae is given.

The fatty acid composition and stable isotope ratios of carbon, nitrogen, and sulfur were analyzed in the protobranch bivalve Acila insignis, a selective detritophage inhabiting subtidal sand sediments of Vostok Bay (Sea of Japan). Soft tissues of A. insignis contained abnormally high concentrations of the polyunsaturated arachidonic acid, 20: 4(n-6), and a rare monounsaturated fatty acid 20: 1(n-13), which distinguishes this species from other bivalves. The high concentrations of these fatty acids in A. insignis, together with the low values of σ34S and the high values of σ13C and σ15N, are probably a result of feeding on the microbial food web. Keywordsbivalve mollusks–Nuculidae–feeding–fatty acids–stable isotopes–microbial food web

The mortality rates of the copepodite IV-copepodite V and copepodite V-adult individuals pairs in the populations of one of the most common species of planktonic copepod, Oithona similis, were estimated for the first time in the Barents and White seas. The average parameters were 0.060 and 0.082/day, respectively, in the Barents Sea and 0.166 and 0.120/day in the White Sea. In the Barents Sea, the mortality rates of O. similis significantly increased with an increase in water temperature and in the White Sea a significant decrease occurred with an increase in salinity. It was concluded that the mortality rate of this species is determined first by abiotic factors and that biotic factors are of secondary significance. Keywordszooplankton– Oithona similis –mortality rate–Arctic seas

The oocytes at different stages of development were characterized morphometrically, and seasonal changes in female gonads of the Far-eastern edible holothurian Cucumaria japonica (Semper, 1868) from the Peter the Great Bay were described. Groups of oocytes and categories of sexual tubules corresponding to different stages of development of gonads were distinguished. Free laying oocytes were divided into several groups, i.e., oocytes 3, 4 and 5. The greatest size of C. japonica oocytes was 460 μm. In various seasons of the year there was greater growth of oocytes in the gonads, which reached its maximum volume during reproduction of the holothurians. The gonads developed asynchronously. All the stages of development were observable simultaneously in the gonads of each individual of this species during the reproductive cycle, and the stage of fast growth prevailed. C. japonica spawned twice a year, in May–June and from July to October. Unreleased oocytes were subjected to resorption.

Regeneration of structures (genital bars and ligaments) which enables ophiuroids to throw away the aboral part of the disc was studied in this work. The succession of disc separation during autotomy has been fixed. It has been revealed that upon restoration of genital bars and ligaments regeneration occurs due to migration of cells from tissues remaining after autotomy, but not due to differentiation of cell elements. The cell sources of regeneration of the studied structures are fibroblasts and sclerocytes.

We found that ligaments connecting the skeletal elements in the arm of the brittlestar Amphipholis kochii, consisted of mutable collagenous tissue (MCT), whose basichistological character is that of numerous processes of juxtaligamental cells penetrating the extracellular matrix. These cells are located in the hyponeural neuroepithelium associated with hyponeural nerves, and were also recorded in the spine ganglia and basiepithelial nervous plexus in the coelomic epithelium. The distinctive feature of juxtaligamental cells is the presence of electron-dense granules in their cytoplasm and a well developed synthetic apparatus. Based on personal and literature data it is concluded that juxtaligamental cells are a part of the nervous system, and their basic function is related to providing MCT with innervation.

A little-known sea krait Pseudolaticauda schistorhynchus from the northern waters of New Guinea Island (Bertrand Island) is described. We note the considerable remoteness of this record from the main species range and its closeness to the distribution area of the closely related species P. semifasciata, which some authors consider to be a northern subspecies widely distributed in the eastern Pacific. The examined specimen is undoubtedly P. schistorhynchus. The boundaries of the two species ranges and keys for the identification of species of the genus Pseudolaticauda Kharin, 1984 are given.

Based on the analysis of original material (52 specimens of Pallasina barbata larvae and juveniles), sampled in the Peter the Great Bay (Sea of Japan) from 1992 to 2006, the ontogenetic stages of this species were described for the first time. It is shown that P. barbata has a planktonic larval stage in its development. The major morphologic features that are typical for larvae and juveniles during their development were revealed. It was shown that snout length, head length and pectoral fin size are increased with growth; at the same time body height and eye diameter are decreased, and the nature of larval pigmentation is changed. The main differences between P. barbata and close species are shown. Original illustrations of larvae and juvenile are provided.

This paper deals with the dendritic field structure of three large ganglion cell types in the retina of a marine teleost, Pholidapus dybowskii. Cells were retrograde labeled with horseradish peroxidase applied to lesioned fibers of the optic nerve. Their morphology was studied in wholemounted retinae. Dendritic fields of αab cells were more complex. Their structural complexity measured using Kolmogorov and information fractal dimensions exceeded significantly those of αa and biplexiform cells. The latter two types exhibited no significant differences in complexity and spatial heterogeneity of dendritic field. The cell types studied differed dramatically in the relationships between fractal and nonfractal parameters of their dendritic arbors. The functional and evolutionary implications of the dendritic field structure of retinal ganglion cells are discussed.

Twenty-two samples of a rare sea anemone Ptychodactis patula having an unusual structure were found in the collection of the Zoological Institute (Russian Academy of Sciences, St. Petersburg). This species was previously referred to the small order Ptychodactiaria, which included only three species. P. apatula was known only from the coasts of Norway (the type locality), Iceland, and the Bering Strait. Our samples greatly exceed the materials thus far published, both in the number of specimens and their places of discovery.

The first data on features of the biology of the sea anemone Charisea saxicola, which is widespread in the Northwest Pacific, were obtained. That species, inhabiting the littoral of Shikotan Isl. (the Minor Kurile Ridge), belongs by its trophological attributes to nonselective deposit feeders. Animals swallow soil together with the organisms in it, not separating mineral particles from organic ones. Populations of Ch. saxicola are presented by individuals of mail and female sex, however the females prevailed in number. Hermaphrodites and evidence of sex change were not revealed in that species. Females were in the postspawning condition in all settlements. Spermatogenic cells of the new generation at two stages of development were recorded in males.

The first finding of the hydromedusa Hydractinia minima (Trinci, 1903) in plankton of Peter the Great Bay (Sea of Japan) is reported. The hydromedusae are 0.24–0.51 mm in bell diameter and 0.25–0.53 mm in height. The size characteristics of the nematocysts of this species (desmonemes and microbasic euryteles) are given. H. minima is present in the plankton of Peter the Great Bay from June through October at water temperatures of 16.4 to 22C with the highest mean monthly density of 151 ind./m3. The finding of H. minima in Peter the Great Bay extends the area of this species in the North Pacific to the low-boreal subzone.

The microscopic anatomy and ultrastructure of a Polian vessel have been studied in the sipunculan Thysanocardia nigra Ikeda, 1904 from the Sea of Japan using the methods of histology and electron microscopy. We describe ultrastructural features of the inner and outer coelothelium, which is constructed of podocytes and multiciliary cells. Between the processes of the podocyte cells, we found double diaphragms that are considered characteristic macromolecular filters. We conclude from an analysis of the ultrastructural features of the vessel wall that coelomic fluid may be filtered from the tentacular coelom to the trunk coelom via the wall of the Polian vessel.

This research is part of a study on the ultrastructure of coelomocytes and cellular complexes from the body cavity of sipunculans. New free-swimming elements called microvillar cells in the trunk coelom of Thysanocardia nigra Ikeda, 1904 are examined using transmission electron microscopy. The cell harbors a giant vesicle filled with a fibrous matrix and rosettes of minute osmiophilous granules. The nucleus is peripheral, and a few cell organelles are situated between the cell membrane and the vesicular membrane. The cell membrane bears numerous microvilli with enlarged apical points. Numerous small microvillar vesicles swimming in the coelomic fluid separate from the microvillar cells. The functional morphology of coelomocytes and cellular complexes is discussed.

The ultrastructure of the tentacles was studied in the sipunculid worm Thysanocardia nigra. Flexible digitate tentacles are arranged into the dorsal and ventral tentacular crowns at the anterior end of the introvert of Th. nigra. The tentacle bears oral, lateral, and aboral rows of cilia; on the oral side, there is a longitudinal groove. Each tentacle contains two oral tentacular canals and an aboral tentacular canal. The oral side of the tentacle is covered by a simple columnar epithelium, which contains large glandular cells that secrete their products onto the apical surface of the epithelium. The lateral and aboral epithelia are composed of cuboidal and flattened cells. The tentacular canals are lined with a flattened coelomic epithelium that consists of podocytes with their processes and multiciliated cells. The tentacular canals are continuous with the radial coelomic canals of the head and constitute the terminal parts of the tentacular coelom, which shows a highly complex morphology. Five tentacular nerves and circular and longitudinal muscle bands lie in the connective tissue of the tentacle wall. Similarities and differences in the tentacle morphology between Th. nigra and other sipunculan species are discussed.

Free-floating coelomocytes in the tentacular coelomic cavity of the sipunculan Thysanocardia nigra Ikeda, 1904, were studied using light interference contrast microscopy and scanning and transmission electron microscopy. The following coelomocyte types were distinguished: hemerythrocytes, amoebocytes, and two morphological types of granular cells. No clusters of specialized cells that had been reported to occur in the trunk coelom of Th. nigra were found in the tentacular coelom. The corresponding types of coelomocytes from the tentacular and trunk coelomic cavities were shown to differ in size. These two coeloms are completely separated in sipunculans.

The microscopic anatomy and ultrastructure of nephridium have been studied in the sipunculan Thysanocardia nigra Ikeda, 1904 (Sipuncula, Sipunculidea) from the Sea of Japan using histological and electron microscopic techniques (SEM and TEM). This paper describes ultrastructural features of nephridial epithelium, muscle grid, and coelomic epithelium on the surface of the nephridium, the area of the ciliary funnel, and the tongue. Several types of cells were distinguished in the excretory tube of the nephridium: (1) a columnar epithelium of the excretory bunches; (2) a cubical or flattened epithelium of flask-shaped infoldings; and (3) granulocytes that migrate from the coelom to the extracellular matrix of the nephridial wall. The system of podocytes and multiciliary cells were described in the nephridial coelothelium. Two types of secretion of nephridial epithelium have been discovered: a merocrine secretion of columnar cells and an apocrine secretion of cells of the flask-shaped infoldings. Using ultrastructural data, two zones of filtration through the wall of excretory tube have been found, namely (1) the tips of flask-shaped infoldings (via the extracellular matrix and microvillary canals between the epithelial cells) and (2) areas between the flask-shaped infoldings (via the contacts of podocytes, extracellular matrix, and the basal labyrinth of the columnar cells). Unlike previously studied representatives of the genus Phascolosoma, no coelomic epithelium is present on the tips of the flask-shaped infoldings in Th. nigra. This data on the anatomy and histology allow us to conclude that the funnel only works like a gonoduct.

The ultrastructural characteristics of coelomic cell complexes in the coelomic fluid were investigated with the use of transmission electron microscopy on the example of Japanese sipunculid. In the sipunculid coelom, complexes consisting of several cells were found for the first time: the central glandular cell and the outer layer of podocytes. Peculiar cell complexes (urns), comprising by ciliary and granular cells, were described in Thysanocardia for the first time. It had been proposed that both types of coelomic cell complexes dissociated from extensive chloragogenic tissue clusters on the intestine surface of Th. nigra. The variety of cell complexes in the coelom of other sipunculid is discussed.

The protein content in the dry body weight of the starfish Odontaster validus is 30%. The composition of amino acids is characterized by a very high level of glycine (27%). Glutamic acid (Glu) in a concentration of 10 mM/liter in seawater causes an increase in the metabolic rate of starved O. validus. As the period of starvation increases, this reaction is enhanced. A two-hour exposure to kynurenic acid (Kyn) in a concentration of 0.1 mM/liter blocks the reaction to glutamic acid.

Four types of blood capillaries of the phoronid Phoronopsis harmeri are described. These are capillaries of the tentacles, of the body, of the stomach plexus, and of the vasoperitoneal tissue. The wall of capillary consists of cells of the coelomic lining, a layer of extracellular matrix, and separate endothelial cells. Myoepithelial coelomic cells of tentacle capillaries contain cross-striated fibers. In capillaries of the body and the stomach plexus, the myofilaments are smooth. In the cells of the wall of vasoperitoneal tissue capillaries, myofilaments are lacking. The cells of the vessel wall of the tentacles, the body, and the vasoperitoneal tissue bear a single cilium. The cells of capillaries of the stomach plexus lack a cilium. The ultrastructure of erythrocytes and amebocytes is described. In the cytoplasm of erythrocytes, there is a basal body. It is assumed that erythrocytes originated from the ciliary cells of the wall of the blood vessels.

The ultrastructure of the wall of the main blood vessels of the phoronid Phoronopsis harmeri is described. The walls of the lophophoral and left lateral vessels consist of myoepithelial cells of the coelomic lining (peritoneal cells), a thin basal lamina, and an incomplete endothelial lining. In the head region of the body, the wall of the medial vessel consists of myoepithelial cells of the coelomic lining (peritoneal cells), a basal lamina, and true muscular endothelial cells. The anterior part of the medial vessel functions as the heart. In the anterior part of the body, the medial vessel wall consists of five layers: the external nonmuscular coelothelium, a layer of the extracellular matrix, the internal muscular coelothelium, an internal layer of the extracellular matrix, and an incomplete endothelial lining. The complicated structure of the medial vessel wall may be explained by the superimposition of the lateral mesentery on the ordinary vessel wall.

This paper describes the morphology and ultrastructure of lophophoral organs and adjacent epithelia of lophophoral concavity and anal papilla in the phoronid Phoronopsis harmeri. The lophophoral organ consists of two parts, which are connected to each other with a spacious foramen. The lower part is sack-shaped and the upper part is hood-shaped. Inside the lower part, there is a large cavity, which communicates to the environment with a narrow slit. Nephridiopores are directed towards these slits. Three types of lophophoral organ epithelia have been distinguished, all of them comprised supporting and glandular cells. Cells with inclusions resembling bacteria were found in the inner epithelium of lophophoral organs. The epithelium of the anal papilla consists of supporting and numerous glandular cells. The formation of spermatophores in lophophoral organs, as well as the structure and functions of glandular cells in epithelia of lophophoral organs and anal papilla, are discussed.

Two specimens of Liparis frenatus (Gilbert et Burke, 1912) of 30.1 and 55.5 mm in TL were recorded in Russian waters of the Sea of Japan for the first time. Five specimens of a poorly known species, L. kusnetzovi Taranetz, 1935, were found. Data on the areas of capture and counts of plastic and meristic characters are provided. The specimens of L. frenatus and L. kusnetzovi are described and compared to the closest species of the genus. KeywordsSea of Japan– Liparis frenatus – L. kusnetzovi –first record–description–characters–longitudinal diameter of sucking disk

The microscopic anatomy and ultrastructure of the nervous system of Phoronopsis harmeri was investigated using histological techniques and electron microscopy. The collar nerve ring is basically formed by circular nerve fibers originating from sensitive cells of tentacles. The dorsal nerve plexus principally consists of large motor neurons. It is shown for the first time that the sensitive collar nerve ring immediately passes into the motor dorsal nerve plexus. The basic components of the nervous system have similar cytoarchitectonics and a layered structure. The first layer is formed by numerous nerve fibers surrounded by the processes of glia-like cells. The bodies of glia-like cells constitute the second layer. The third layer consists of neuron bodies overarched by the bodies of epidermal cells. The giant nervous fiber is accompanied by more than one hundred nerve fibers of a common structure and, thus, marks the true longitudinal nerve. The phoronids possess one or two longitudinal nerves. It is supposed that the plexus nature of the nervous system in phoronids may be related to their phylogenesis. A comparison of the nervous system organization and body plans among the Lophophorata suggests that the nervous system of phoronids cannot be considered as a reductive variant of the brachiopod nervous system. At the same time, the structure of the nervous system of bryozoans can be derived from that of phoronids.