日本産ガンギエビ科魚類の研究 (第1報)

10種の卵殼に就て

抄録

The present paper gives the results of my observation of the egg-capusules of the 10 species belonging to the family Rajidae, viz., Raja kenojei, R. garmani, R. macrophthaima, R. hoilandii, R. fusca, R. meerdervoortii, R. putchva, R. parmifera, R. iso-trachys and R. diplotaenia, which have been collected in Japan and adjoining waters.
Based upon the external as well as the histological features it was found that the capsules are divided into four types, which are called herein types Kenojei, Soldatovi, Parmifera and Isotrachys respectively.
Type-Kenojei: This type involves Raja kenojei, R. garmani, R. macrophthalma, R. holiandii, R. fusca and R. meerdervoortii meerdervoortii. The egg-capsule is of smooth surface and with short projections (horns) at the four corners (Fig. 1, KE, GA, MA, HO, FIT, ME). Of 6 species aforementioned the last two ones are closely related, characterized by having the horizontal thin horny layers, and the upper most layer bearing minute tubercles on the surface (Fig. 2, FIT, ME). In the other 4 species, however, a pulpy layer are found to exist between outer and inner layers (Fig. 2. KE, GA, HO, MA).
Type-Pulchra: This type involes Raja pulchra only. The external form of the capsule is chara3terized by having a broad notch along the both lateral sides and a very short flattened horn at each corner (Fig. 1. SO). The outer layer of the capsule is composed of several zones of fibrous tissue running lengthwise series. The fibers become larger toward the surface, the ones on outermost layer usually tubular and easily spill by themselves without giving any strong friction. The surface of the capsule, therefore, is rather rough (Fig. 2. SO).
Type-Parmifera: This type is represented by Raja parmifera. The capsule closely related to that of Type-Kenojei, but the horns rather long and flattend (Fig. 1. PA), the outermost horny layer is represented by stout linear ridges run-fling lengthwise series (Fig. 2. PA).
Type-Isotrachys: This type is exemplified by Raja isotrachys and R. dipiotaenia. The horns are very long and filamentous, the anterior ones much longer than those of the posterior ones (Fig. 1. IS, DI). The outer horny layer is peculiar, armed with numerous series of minute velvety pricks (Fig. 2. IS, DI).