The larval development of the land crad, Cardisoma hirtipes DANA, reared under laboratory conditions, is described and illustrated. The larvae passed through five zoeal stages before they molted to the megalopal stage. Only a few zoeas succeeded in metamorphosing into the megalopal stage in 13 days at a water temperature of about 28℃. Larval relationships are discussed among C. carnifex, C. hirtipes and C. guanhumi, C. hirtipes and C. guanhumi shares most of the essential features in zoeal and megalopal stages, but C. carnifex is distant from these two species in having spinous abdominal segments and an elongate telson.

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Relative length of the carpus to the palm of the second pereopods was investigated in relation to body size of individuals in Macrobrachium nipponense (DE HAAN) and Macrobrachium BATE, and contrasting results were obtained between the two species. The relative length of carpus to palm will be informative in their identification.

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[in Japanese]

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Larvae of five species of Japanese xanthid crabs, Medaeops granulosus, Paraxanthias elegans, Novactaea pulchella, Pilumnus vespertilio and P. scabriusculus, were reared in the laboratory from hatching to the last zoea or megalopa stage. They were fed on Artemia salina (L.) nauplii. Their zoeae are described and illustrated in detail, and compared with xanthid crab zoeae in the literature. Under the laboratory conditions, each species has a definite number of zoea stages ; M. granulosus, Paraxanthias elegans and Pilumnus scabriusculus have four zoea stages, Pilumnus vespertilio has three, and N. pulchella has two. The xanthid subfamilies can be classified into eight groups based upon the morphological feature of the antenna II and the setal formulae of endopods of the maxillae I and II of the known xanthid crab zoeae. As a result of these zoeal characters, the genus Halimede appears to have a closer relationship to the subfamily Pilumninae rather than to the subfamily Xanthinae. Furthermore, a key is given to the zoeae of twenty-seven species of xanthid crabs from Japan. The most primitive stock among the xanthid crabs may be xanthinid group including genus Halimede mentioned-above. The ancestral stock provably divided into four lines ; one leading to the Hyperolissa and Zalasinae, one to the Trapeziinae, one to the Pilumninae, and one to the modern Menippinae including the genera Menippe and Sphaerozius.

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[in Japanese]

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The life histories of Haustorioides japonicus KAMIHIRA and H. munsterhjelmi (OLDEVIG), amhipods were investigated in the sandy beaches of the southern part of Hokkaido, Japan. There was a delicate difference in the alternation of generations of H. japonicus in each study. A bivoltine reproductive cycle was exhibited in Date-usu : a generation recruited in spring produced in summer a generation that overwintered and reproduced in the following spring. On the other hand, the univoltine reproductive cycle was observed in Hakodate. In Iwanai and Setana, the majority of numbers were univoltine, and a small number were bivoltine. It seems that the main reason for the differences in alternation of generation was the level of the sea water temperature in spring and summer in each study area. H. munsterhjelmi showed a univoltine reproductive cycle in Mukawa-shiomi. The habitat of these amphipods was observed in the littoral zone and the sublittoral zone. The breeding season was spring or summer.

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Previously, the third to fifth zoeal stage and one megalopa stage of Tritodynamia horvathi NOBILI found in the plankton had been reported by the junior author (1983) . Recently, the present authors collected the berried female crabs of this species from the Yatsushiro-Kai, Kumamoto Prefecture. These crabs were reared in the laboratory for observation of the larval development. In the present paper, the larvae of the first and second zoeal stages of this species are described and illustrated, and also compared with these zoeal stages of a relative species, T. japonica ORTMANN reported by TERADA (1987).

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Early and middle larval development of P. penicillatus reared in the laboratory for 160 days was examined. Although no puerulus was obtained, the larval development during the experiment was morphologically divided into seven stages. Average molting intervals were around six days for instars I-III and ten days after instar V. In most cases, one pair of setae was regularly added on the exopod of the 3rd maxilliped after instar II and those on the exopod of the 1st and the 2nd pereopods after instar V. Growth in body length and other body parts was indicated as an exponential curve. The growth patterns of the antennular and the antennal length and the abdominal width were changed at stage V. Morphological variations in larval development among individuals in the same instar were observed after instar IV. Early-stage phyllosomas of P. penicillatus were distinguished from other phyllosomas of the present genus in having two spinules on the proximal segment of the maxilla, in stead of three spinules in others.

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[in Japanese]

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