The changes of the cheliped following the growth of the carapace were studied on the Carcinoplax longimanus (DE HAAN) which were collected by trawlnets and dredges in the East China Sea during these twelve years from October 1953 to July 1964, and the following results were obtained. The dimensions measured for the present study are shown in Fig. 1. Carapace length: Length from the frontal margin to the posterior margin of the carapace. Carapace width: Width from the left margin to the right margin of the carapace. Palm length: Length from the tip of the immovable finger of the cheliped to the boundary between the cheliped and the carpus. Merus length: Length from the boundary between the carpus and the merus to the boundary between the merus and the ischium. 1) The relative growth of the width of the carapace on the length of the carapace is shown in Fig. 4 (female) and Fig. 5 (male). A linear regression is fit in female, but an inflection is shown at about 50mm in carapace length in male. 2) The relative growth of the length of the merus of the cheliped on the length of the palm represents good fit to linear regression in female (Fig. 6) and male (Fig. 7). 3) The relative growth of the length of the palm and the merus of the cheliped on the length of the carapace is shown as linear regression in female (Figs. 8 and 10), but a distinct inflection is noted at about 40 to 45mm in carapace length in male (Figs. 9 and 11). 4) Rapid growth of the cheliped after the growth inflection at about 40 to 45mm in carapace length in male seems to be related with the increasing of the copulation function.

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Following four species, namely, Pandalus hypsinotus BRANDT, P. borealis KROYER, P. goniurus STIMPSON, Pandalopsis dispar RATHBUN, are found as shrimp resources of the Bering Sea. In P. borealis, the most important shrimp resources in the sea in question, the body-length, from postorbital margin to tip of telson, ranges 72.0〜120.0 mm in female, 41.5〜98.0 mm in male. It seems that the sexual change of this shrimp takes place in body-length from 70 mm to 100 mm. Spawned shrimps, pre-eyed egg, eyed egg-arrying ones and those having ovarian eggs occur during the period from posterior half of April to September. Egg diameter is measured 1.02×0.78 mm in pre-eyed eggs, 1.43-0.96 mm in eyed eggs. Number of eggs laid beneath abdomen has a positive relation with body-length. It is 425-2045 (1207 on average) in eyed-egg, 724-2606 (1776 on average) in pre eyed one.

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[in Japanese]

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A number of specimens of Hexapus sexpes (Fabricius) have been obtained by the writer from the waste of the trawl-net in Mikawa District, Aichi Prefecture. These speimens are enormous in size compared with those hitherto recorded by the previous authors (cf. page 49). The biggest female specimen measured 19.5 mm in the length of carapace and 33.0 mm in the width of same. According to Dr. T. SAKAI, such big specimens of Hexapus sexpes are not uncommon in Suruga Bay (off Numazu City) and Sagami Bay (off Enoshima). The literatures and references of this species, as well as the congeners are enumerated in the Japanese text of this paper.

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Lernaea elegans LEIGH-SHARPE, which is a commonly Japanese parasitic copepoda, known as "anchor worm", is found in the skin of Oryzias latipes (TEMMINCK et SCHLEGEL) -one of the commonenest fresh-water fish in Japan. In natural condition, it looks like a small yellowish green straw sticking into the skin of the host. The anchor-like horns of the cephalothorax penetrate into the muscle through the integument of the host. They sometimes reach to the pericardial or peritoneal cavities. The infected portions of the host are red from blood that continually oozed out and often growing into a gall. This paper deals with a histological study of the infected portions of the host and the life cycle of the parasite.

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An interesting habit in some of the younger fish belonging to the Suborder Stromateina, that accompanying the jellyfish, is well known as an example of commensalism. In the young crab such habit as mentioned above, has not yet been known. On October 5, 1962, two individuals of jellyfish, Rhopilema esculenta KISHINOUYE, were obtained off the coast of Enoshima in Sagami Bay and were reared in an inspection tank of the Enoshima Aquarium in Kanagawa Prefecture. They were consecutively bred till October 22, and the attention of the author was attracted to one of the specimens which was accompanied with two small crabs. The small crab was identified as a juvenile male of Charybdis cruciata (HERBST), measuring 9.7 mm in carapace length and 12.9 mm in carapace width. The life history of Charybdis cruciata, is unknown at present, but it seems to be similar to that of the related species, Charybdis japonica A. M.-EDWARDS. In most of the Brachyuran carbs, the habitat and habit of the yonnger stage -Megalopa and early crab-stage- are gradually corresponding to those of the adult in the course ot the development. It is noteworthy that the young of Ch. Cruciata has been found living among the oral arms of the jellyfish, however, whether this fact is due to commensalism or to a mere accident is not certain to conclude at present. The author regards, however, the ecological terminology "exploitation" may be properly applied for the present case.

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Two living specimens of megalopa of P. depressa tuberculata LAMARCK were obtained at the coast of Manazuru, Sagami Bay, in early autumn of 1963 and also in early summer of 1964, and were reared in the aquarium until they reach the first crab stage. These specimens have been compared with those of P. dentipes DE HAAN. The data is summarized in the following. The megalopa stage: a) The carapace is sparingly covered with a fine tomentum, whereas, it is naked P. dentipes. B) The rostrum is well projecting forwards and bified at the tip, whereas, it is rather short and broadly bilobed in P. dentipes. C) The exopod of the external maxilliped is composed of one segment, it is two-segmented in P. dentipes. D) The difference in number of plumose setae in the exopod of the last pleopod between these two species is shown in table 1. The first crab-stage: Aside from the various morphological points of difference between the young crabs of the two species, the carapace of P. depressa tuberculata is covered with tubercles and short hairs, whereas, it is not tuberculated but only haired in P. dentipes.

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Inquiries have been made into the ranges of crabs found in the estuaries of the southern Kanto district (Tokyo Metropolis and Kanagawa Prefecture). Only a few number of species may be seen in the river mouth of the torrential rivers such as, Hayakawa, Sakawagawa, Hanamizugawa and Sagamigawa. They are Varuna litterata, Eriocheir japonicus, Sesarma haematocheir, S. dehaani and S. intermedia all belonging to estuarine crabs. On the other hand, in the estuaries of the slowly flowing rivers such as, Sakaigawa, Namerigawa, Tagoegawa, Moritogawa, Hirasakugawa, Tamagawa and Arakawa, som marine crabs such as, Philyra pisum, Charybdis japonicus and Hemigrapsus penicillatus may be seen together with those estuarine crabs mentioned above. Among these estuarine crabs the habitat of Paracleistastoma, Scopimera and Ilyoplax extend towards fresh water region, and those of Sesarma haematocheir and its relatives (S. denhaani and S. intermedia) into the swamns and marshes and further towards the land near the river.

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