One male specimen of the Cancroid Crab was obtained by a smelt-beam trawl from a depth of 15m, off Kushiro, the Pacific coast of Hokkaido, on November 16, 1979. It was identified by Dr. T. SAKAI of the Carcinological Society of Japan as Cancer magister DANA. This crab is one of the important provision resources in U.S.A. (Known as the dungeness crab or common edible crab), ranging along the Pacific coast of North America, from Unalaska, Alaskan Peninsula, south-ward to Montebery Bay, California. It has recently been imported from America to Japan as an edible crab, sold at the markets of Tokyo and Yokohama by the false name of "American swimming crab". Cancer magister is morphologically characterized by having the carapace widest at the last or tenth antero-lateral tooth, and the antero-lateral teeth are low and their tips directed forwards. The postero-lateral borders are unbroken and entire. Fingers of chelipeds are not pigmented with black color. This crab was obtained for the first time in Japan as well as in the north-western Pacific areas. The author is not certain whether this crab was migrated from northwestern coast of America of Alaska, by influence of the cold northern current, or its young or larval crab had been transported by means of the ballast water tunk of a ship. On the other hand, the author's interest has been aroused by the fact that the five American and Alaskan flounder-Embassichthys bathybius had been recorded for the first time in the Pacific coast of Hokkaido by AMAOKA et al. in 1978 (loc. cit.).

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Twelve species of Cladocera belonging to the families Chydoridae and Macrothricidae are discussed and illustrated from Punjab, India. The assemblage, of which three species are new includes : Alona dhilloni sp. nov., Alona pulchella KING, Biapertura sp. indet,, Camptocercus kapuri sp. nov., Ledigia ciliata GAUTHIER, Oxyurella singalensis (DADAY) , Chydorus sp, cf. ciliatus POGGENPOL, Chydorus eurynotus brehmi BISWAS, Chydorus parvus parvus DADAY, Dunhevedia crassa KING, Ilyocryptus spinifer HERRICK, aed Ilyocryptus bhardwaji sp. nov.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Zoeae of the five varunid crabs, Eriocheir japonicus DE HAAN, Hemigrapsus sanguieneus (DE HAAN) , H. Penicillatus (DE HAAN) , H. longitarsis (MIERS) and Gaetice depressus (DE HAAN) , of the family Grapsidae were successfully reared in the laboratory from hatching to the megalopa stage. Artemia nauplii were given as food. In this paper, the zoeal stages of all the species are described in detail and those of H. longitarsis are figured. The zoeae of these species are compared with those of the other members of the Subfamily Varuninae so far studied by previous writers. As in H. nudus, H. oregoniensis and Acmaeopleura parvula, the five species herein dealt with have five zoeal stages before transforming into the megalopa. The zoeae of the varunid crabs are very similar in structure one another, although minor differences are found among different genera. As to the five species, zoeae of genus Hemigrapsus are different from those of the other two genera (Eriocheir and Gaetice) by the occurrence of one small seta on the anterior lateral surface of scaphognathite in the last stage and also in setation of basal endite of maxilla I in stage IV. Furthermore, zoeae of the two species of genus Eriocheir and the five species of Hemigrapsus can be distinguished from those of the genera, Acmaeopleura and Caetice, by having lateral carapace spines. Among the nine known species differences are found in the presence or absence of chromatophores on protopod of maxilliped II, mid-lateral spines on abdominal segments II and III, setation on endopod of maxilliped II, and the type of antenna II.

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Larvae of six species of the subfamily Acanthonychinae (family Majidae) : Pugettia quadridens quadridens (DE HAAN), P. q. intermedis SAKAI, P. incisa DE HAAN), P. similis Rathbun, Menaethius monoceros (LATREILLE) and Huenia proteus DE HAAN, were successfully reared in the laboratory from hatching to the megalopa stage by feeding on Artemia nauplii. The numbers of zoeal stages are only two in the six species. These zoeae may be classified into two groups. In the first group. to which the genus Pugettia, chromatophores are present at the bases of rostral and dorsal carapace spines and on protopod of maxilliped I, setation of endopod of maxilla I is 4・0-1, that of inner lobe of coxal endite of maxilla II is 1:3, caudal furca of telson is twice as long as width of telson, and the articulation of telson occurred in stage II. In the other group including genera Menaethius and Huenia, no chromatophores are present at the three parts, setations of endopod of maxilla I and inner lobe of coxal endite of maxilla II are 4・1-0 and 1:4, caudal furca and width of telson are about equal in length, and the articulation disappears in stage II. Specific differences in the characters of zoeae are as follows. In genus Pugettia (the first group), P. incisa has setation of 3 on endopod of maxilla II, but the other three species have 4. Furthermore, P. q. intermedis has nine setae on basal endite of maxilla I in stage II, in contrast, P. q. quadridens and P. similis possessing ten in the same stage. In the two species of the second group, M. monoceros has rostral spine, but neither dorsal nor lateral ones on carapace and setation of 5 on endopod of maxilla II, whereas H. proteus having rostral and dorsal spines, and setation of 4.

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Diagnostic features for the identification of postlarval Penaeus found in the shore waters of the Philippines are described and categorized based on specimens caught from the wild and those hatched and reared in the laboratory. Differentiating features for postlarval Penaeus are given which include the relative length of the antennular flagellum, the shape of the rostrum and number of rostral teeth, the antennal spine, the spinules on the dorsal carina of the sixth abdominal segment, and chromatophore patterns. Postlarval Penaeus were classified into two species and two groups as follows : (1) P. monodon, larger in size with dense chromatophores, and the long inner antennular flagellum being more than 2.0 times the outer antennular flagellum ; (2) P. semisulcatus, the inner flagellum being 1.6 to 2.0 times the outer antennular flagellum, with the absence of chromatophore on the middle portion of the telson and uropods ; (3) P, merguiensis group, less pigmented, the inner flagellum being less than 1.6 times the outer flagellum and (4) P. japonicus group, a short rostrum, presence of spinules on the dorsal carina of the sixth abdominal segment, and dense chromatophores. The determinations were confirmed by rearing experiments.

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The present paper deals with allomatric growth between carapace length and carapace width of tadpole shrimp, Triops granarius (LUCAS) living in the paddy field, Takatsuki, Osaka Pref., with special reference to its population.

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[in Japanese]

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A simple technique is described for obtaining well-spread metaphases from solid tissues of Crustacer. The procedure of chromosome preparation was as follows : 1) Specimens were injected intraperitoneally with colchicine solution at the dosage of I pg per 1μg body weight five hours before being dissected. 2) Remove antennal gland and testis, and cut them into 3mm pieces where necessary. 3) Place tissue pieces in the hypotonic solution (distilled water or 0.01M KCl) for 10 minutes. 4) Add small quantity of Carnoy's fluid (3:1 ethanol acetic acid). 5) Fix in at least two changes of Carnoy's fluid for at least 15 minutes each. 6) Pick tissue pieces up from Carnoy's fluid by a forceps, and tap to spread them on a slide glass for a proper density of cells. 7) Drop Carnoy's fluid on the slide from a fine pipet. 8) Dry quickly by flaming. 9) Stain with 2% Giemsa for 15 minutes. Large numbers of slides of chromosome can be made easily and rapidly using this procedure.

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The habitats, nest burrows, hibernation, awaking, molting, copulation. oviposition, egg-bearing, zoea-liberation (spawning) , beach landing of the tiny young, and so on of the land-crab, Sesarma (Holometopus) haematocheir (DE HAAN), were studied from April, 1979 to November, 1980. Field observation was made in the rocky shore near the Sado Marine Biological Station of Niigata University located on the west coast of Sado Island in the Japan Sea. When the ground temperature (GT) fell gradually 16℃, the crabs emerged from the nest and went to the beach for feeding. Molting occurred from late June to middle September, although in mother crab it took place since August after the release of zoeal larvae. Copulation was found from late June to early August, and the frequency of copulation and next oviposition in one spawning season were two to three times per crab. Zoea release took place almost every night about one or two hours after sunset (ca. 19:00) during the period from late July to early September, although no spawning was encountered in stormy weather. Beach landing of an infant crab just metamorphosed from megalopa was seen in late September, and the first molting occurred in a pool two or three days after landing. Difference between the spawning behavior of this land-crab occurring in the Japan Sea coast and in the Pacific coast was discussed in relation to the difference of the tidal changes in the both coasts.

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The ecological distribution of phytal amphipods on seaweeds were investigated in a Sargassum bed at the coast of Tomioka Peninsula, Amakusa, Kyushu. Eight plants of 4 Sargassum species were collected underwater by the vertically stratified sampling method in May when these seaweeds fuliy grown up. By this sampling, 10 species of caprellids and 21 species of gammarids were obtained. The similarities among epiphytic amphipod assemblages of each host plant were analyzed for Caprellidae and Gammaridea respectively. These assemblages resembled each other, consequently it was speculated that these epiphytic amphipods generally have no specific preference to the host plants. Simultaneously, two groups were recognized in both taxa, namely, one group consists of S, patens and S. horneri which were collected in the outer part of the Sargassum bed, another is S. thunbergii and S. hemiphyllum which mainly flourish inside. The difference seemed to be caused by the factors which related with wave action or other hydrodynamic conditions. In the vertical distribution of the biomass of each alga, the weight of higher part was normally heavier than that of lower part, and this tendency was also observed in the individual number of amphipods on each part. Vertical distribution of 6 species of amphipods (Caprella decipiens, C. danilevskii, C. tsugarensis, Ampithoe orientalis, Aoroides columbiae, Pontogeneia rostrata) showed high positive correlations with those of seaweeds biomass. Exclusive of S. horneri, C. monoceros and Phliantidae sp. 1 also showed positive correlations with the vertical distribution of seaweed biomass like other species. On S. horneri, however, they mainly occurred on the lower part of seaweed and showed negative correlation.

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[in Japanese]

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