The four extant horseshoe crabs are morphologically so similar to fossil specimens of the genus Mesolimulus that one has referred to them as "living fossils". The recent horseshoe crabs are assigned to two subfamilies, that is, Limulinae and Tachypleinae. The Limulinae includes only one American species, Limulus polyphemus and the Tachypleinae includes three Asian species, Tachypleus tridentatus, T. gigas and Carcinoscorpius rotundicauda. The hybridization experiments revealed that the fertilization could not be accomplished between Limulus and Asian species gametes, while three Asian horseshoe crabs were cross-fertilizable one another. Developmental capacity of hybridized eggs among the three Asian species was not equivalent, suggesting that one had rather not assign three Asian horseshoe crabs to such two diverse genera as Tachypleus and Carcinoscorpius in the current taxonomy. These results are in concord with the idea that American and Asian horseshoe crabs diverged from a common European ancestor (or separate ancestral species) and that the three extant Asian horseshoe crabs diverged from a common Asian ancestor.

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The male of Uropoda (Phaulodinychus) ehimensis HIRAMATSU, 1979, the deutonymph of Uroobovella flagelliger (BERLESE, 1910), the deutonymph, the female and the male of a new species, Uroobovella fistulata, from Japan are described and illustrated.

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Two species, Hyptiotes affinis BOSENBERG et STRAND and Miagrammopes orientalis BOSENBERG et STRAND, are recorded, and a new species, M. oblongus, is described from Taiwan.

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Three species of caprellid amphipods, a new species, Caprella (Caprella) temperativa, C. (Spinicephala) californica STIMPSON and C. (Rostrhicephala) penantis LEACH, were collected from Ogasawara Islands. The new species C. (Caprella) temperativa is distinguishable from related species in the second gnathopod armed with a big poison tooth and without small processes on the second and third segments.

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Six species of monstrilloid copepods, Monstrilla serricornis, M. sp., Cymbasoma longispinosum, C. rigidum, C. morii and C. agoensis, were collected from Ago Bay, Japan, under a light at night. Of which, C. agoensis is a new to science and is easily distinguishable from other species of monstrilloids in the absence of oral cone and in the number of setae on fifth thoracic leg. M. serricornis, C. longispinosum and C. rigidum are new records from^the Japanese waters.

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Larvae hatched from several berried females of Nanosesarma gordoni (SHEN) in the laboratory were reared throughout the zoeal stages on Artemia nauplii as food. The zoea larvae pass through five stages and then metamorphose to the megalopa stage. These zoeal stages are described and illustrated in detail, and discussed in comparison with those of 18 species belonging to the subfamily Sesarminae. The sesarminid zoeae are classified into two groups in the following respects. The first group, to which the genera Sesarma, Sesarmops, Metasesarma and Nanosesarma belong, has the setation of 3・2 in the endopod of maxilla II in all stages and 2:3 in the inner lobe of coxa of maxilla II in the early stages, and is lacking the rudimentary endopod of antenna I. The other group including Cyclograpsus, Chasmagnathus and Helice has 2・2 and 1:3 in maxilla II, and a rudimentary endopod in the last stage. The zoeae of N. gordoni can be distinguished from those of the closely related sesarminid crabs by the setation of 2・3・2・2 on the protopod of maxilliped I.

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It is confirmed that there are following two types of the germ rudiment formation in the integripalpian Trichoptera. Glyphotaelius admorsus belongs to the type which the amniotic fold develops only from the posterior margin of germ disk, and Neosererina crassicornis belongs to another type which the folds develop from all around the margin. The Glyphotaelius type is similar to those of the annulipalpian Trichoptera, and zeugropteran and monotrysian moths in the state of the germ rudiment formation. The Neosererina type rather resembles those of the ditrysian Lepidoptera in the state. The results of the present study suggest that there is an akin relationship between the Trichoptera and Lepidoptera.

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A remarkable macrocephalic new species of Damaster belonging to the subgenus Acoptolabrus is described under the name of mirabilissimus from South Korea. This species is distinguished from other species of the subgenus by conspicuous hypertrophy of the head and features due to it, including the shape of prothorax. Some of the outstanding characters of this species are unusually developed anterior tooth of right retinaculum, strongly projecting median tooth of mentum, extraordinarily constricted pronotum without posterior marginal setae. The genitalic characters of the male are also very distinctive.

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In our previous paper we have reported four color types of very common freshwater goby, Rhinogobius brunneus (TEMMINCK et SCHLEGEL), found in Sado Island on the Japan Sea (INOUYE, MATSUMOTO and HONMA, 1978). This Island lies 32 miles west of Niigata City. Chaenogobius annularis GILL, consisting both of brackish and freshwater dwellers, is also a common freshwater goby widely distributed throughout the Japanese Islands. Based chiefly on the color pattern and blotches on the dorsal and caudal fins as taxonomic characters, NAKANISHI (1978 a, b) reported that this goby can be classified into 3 different types : middle-reach-, freshwater-, and brackish water types. To make comparison with our previous paper and NAKANISHI'S papers, we have investigated the distribution, variability and intraspecific differentiation of this species occurring in Niigata area. The present paper deals with the results obtained in Sado Island. The material consists of 241 specimens collected from 33 locations of 28 rivers, from May to December, 1977. In the present time, the size, shape and darkness of a blotch existed on the caudal peduncle just anterior to the base of caudal fiin were considered as a new taxonomic character, and were verified as valid. So-called middle-reach type was a commonest race throughout the water systems of the Island, and its distributional pattern was similar to that of cobalt type of R. brunneus. The feshwater type was found exclusively in the Kuninaka Plain located in the central part of the Island, and its distributional pattern corresponded to that of orange type, i.e., lacustrine race, of R. brunneus. The brackish type showed a comparatively wide distribution and its distributional pattern was somewhat related to that of middle-reach type. Curiously, in 3 rivers this type was occupied the most upper reaches among these three types. The habitat of C. annularis tended to restrict in the comparatively lower region of the rivers in Sado Island. It was cleared that the habitat of cobalt type of R. brunneus existed in the most upper reaches of the rivers among the gobiid fishes of the Island.

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