1970年,ネパールの水産局長タッパ博士から,日本の皇太子殿下のご研究用として,同国産の多くの魚類標本(ホルマリン漬)が殿下に献上された。それは,1969年5月から7月にわたって,東ネパールのビラトナガールにある養魚兼配苗センターと,中部ネパールのポカーラにある湖水開発企業などの手によって,広く採集されたもののようである。東宮御所の魚類研究室で,それらの魚類標本を整理されたところ,16体のエビが混じっていた。皇太子殿下の思し召しにより,そのエビを私の研究用に賜わることになり,東宮職から1972年4月郵送到着した。私は寡聞にして,ネパールのエビについて報告されたものを知らないので,多大の興味関心をもってつぶさに観察した結果,それらの内4体はMacrobrachium australe,3体はM.palaemonoides,5体はM.sintangenseであり,4体は新種と認めM.nepalenseと命名した。この新種は,従来ヒマラヤ山脈の水域(ダージリングその他)からのみ知られていたM.hendersoniに以ているが,主として第2胸脚の「はさみ」の特徴によってそれと異なる。すなわち,新種にあっては,掌節の内側下辺がやわらかな毛で密におおわれ,可動と不動両指の表面に縦溝が1つも見あたらないのである。

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The anomuran crab, Lithodes longispina SAKAI (Fig. 1), is a species allied to Lithodes turritus and L. aequispina. This crab has been taken from the bottoms, 400-900m deep, off Boso Peninsula and Sagami Bay from March 1969 to March 1971 (Fig. 2, Table 1). Width of carapace ranges from 9.3 to 12.5 cm in the female and from 9.4 to 13.5 cm in the male (Fig. 3). The spawning period of this crab seems to continue from August to October (Fig. 4). The number of incubating eggs was correlated to the carapace width of the crab at the coefficy of correlation, 0.859. The number of eggs ranges from 3,900 to 11,200 per individual female from 9.8 cm to 11.9 cm in carapace width (Fig. 5).

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This paper deals with the anandromous phenomena of megalopa of Varuna litterata (FABRICIUS) (Grapsidae, Varuninae), which was observed at the river mouth of the Hikiji-Gawa, situated on the north-east coast of Sagami Bay. The phenomena were observed in the daytime during the period from Oct. 9th to Nov. 7th of 1972. Tidal influence to the river reaches about 2 km from the river mouth. The adult crab is very rarely found on the northern areas of Sagami Bay, where may be the northern limit of distribution of this species. Each of the megalopa reaches the river mouth from off shore before full tide. The number of megalopa increases to the greatest at the time of full tide after the new moon or the full moon day. The megalopa continues to swim swiftly up the stream, keeping the distance between 10 to 30 cm from the shore. The swarm of megalopae thus reaches even 2 km beyond the limit of tidal influence. The length of carapace of the megalopa varies from 3.7 mm to 4.5 mm, the average size being 4.1 mm.

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Eriocheir japonica mates during the period from the middle of October to the latter part of March and the peak of mating period is from the middle of January to that of February. The mating occus in the inter tidal zone of the neap tide. This crabs usually chose a region nearer the full tide line as a mating place. The mating time is during the tide rising. The crabs showing sexual behavior are more than 3.9cm in carapace width and the smaller crabs which are less than 3.9 cm in carapace width passes the winter in the river. This species changes its nature a few days after having reached the tidal zone and losts its nocternal disposition and comes to behave to the rhythum of an ebb and flow even in the day time. The crabs chose the partners by snipping one another. The opposite sex is recognizd by the degree of the intensity of snipping back. The male crabs living in the river have the second pleopods, but lost them when these crabs come down to the tidal zone for mating. In the laboratory the mating behavior of Eriocheir japonica easily can be observed, by keeping the male and female crabs obtained from the inter tidal zone in aquariums separately, in which 25-30 % sea water is preserved about a week befor pairing. The mating occurs in 25-30 % sea water, in pure sea water and also in fresh water.

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The present author obtained three living specimens of megalopa from Sagami Bay by surface collection, in October of 1970. These larvae have been reared in the aquarium until moulted to the young crabs, which are identified to Hemigrapsus penicillatus. The adult crab is very common in japan, found usually on the rocky and muddy beaches as well as on the beach of pebbles on river-mouth. The larval features of these specimens have been observed and illustrated in this short report, comparing with the larvae of some other related crabs already reported.

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コブカイミジンコ属(Cyprinotus)は,付属肢はCypris型,石殼の背縁部にこぶ状の突起があり,また同殻の前・後縁に沿っていぼ状の小突起群が並ぶ。付属肢や殻の構造はよく似るが,こぶのないイボカイミジンコ属(Heterocypris)と近縁である。主として,アジア・オーストラリアに分布し,現在までに約10種が知られている。日本には,次の2種が見られる。コブカイミジンコ(C.uenoi)。体長♀1.5-2.0mm,♂1.3-1.7mm,こぶは比較的小さい。第2触角・第1胸脚・尾叉に性的2型が見られる。水田に最も普通に見られる種。ゴーシューコブカイミジンコ(C.kimberleyensis)。体長♀0.9-1.2mm,♂はいない。こぶは比較的大きい。汽水域を好むが,淡水中でもよく生存しうる。

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1.ハマガニChasmagnathus convexus de HAANのzoea幼生をBrine shrimpのNauplius幼生を餌料として,実験室で飼育し,第2幼蟹期まで変態させた。2.本種のzoea幼生は4回の脱皮の後,megalopa幼生になる。水温20〜28℃で,脱皮の最も早いもので,5日×4=20日を要した。3.本種のzoea幼生の一般的な特徴について記載し,主要な形態については相川(1933)の方法に従って分類した。4.本種のzoea幼生が4回の脱皮をくり返す過程でみられる主要な形態の変化は,次の如くである。顎脚遊泳毛,腹部体節,尾節内側の刺毛,色素胞,小顎各部の剛毛,第1触角の長毛,etc.5.本種の2nd zoea及び3rd zoeaでは,megalopa幼生の器官原基が現われ,4th zoeaで著しく長大に発達する。主な器官原基は次の如くである。第2触角内分肢原基,腹肢原基,胸肢原基,第3顎脚原基,鰓原基。6.本種のmegalopa幼生の形態について記載した。7.本種の第1幼蟹期について記載した。

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The paleo-ecological method of studies for the fossil barnacles collected from the Narita formation of Japan proper is discussed in this paper, referring to the ecological information of barnacles in a living state. The fossil barnacles obtained from the pleistocene beds keep well-defined coloring on the shell plates. Typical hosts of the fossil barnacles are pelecypode species. In the case that the fossil barnacles had been removed from certain hosts, the original hosts are possible to presume by the ornamentati on printing the fossil barnacle bases. It is known that the shell plates of barnacles in a living state are almost attacked with boring algae (Parke & Moore, 1935). The same evidences are also founded in the barnacles obtained from various pleistocene beds at the Narita formation.

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