浮游性魚卵

The present paper, the sixth o f the series of the pelagic fish eggs from Japanese waters, contains the figures and descriptions of the egg development and hatched larvae of 22 species as well as early embryonic development of a single species, Cirrhilabrus temmincki Bleeker, belonging to the suborder Labrina. The eggs of this suborder, excepting ellipsoidal egg of Callyodon ovifrons (Temminck et Schlegel), are globular in shape, 0.5-1.1 mm in diameter, containing a single colorless or yellow oil globule measuring 0.07-0.21 mm in diameter. The egg membrane is smooth, without any conspicuous structure, the yolk not segmented, the perivitelline space narrow. During the course of the egg and larval development only the melanophores appear. The newly hatched larvae have ovoid yolk sac which is usually protruding anteriorly beyond the head, and the oil globule is situated in the anterior part of the yolk. The number of myotomes of the hatched larva is about 27. The location of the melanophores of the hatched larva changes greatly during the larval development. Soon after hatching, serration appears in many species on the fringe of the marginal fin. The eggs belonging to Labrina can be divided into 4 groups according to the situation of the melanophores at hatching, and the species belonging to each groups of 1-4 are as follows : 1. No pigment-cell developed in the egg......Labrina Nos. 1-3. 2. Melanophores are seen only on the body......Pseudolabrus japonicus (IIouttuyn), Halichoeres poecilopterus (Temminck et Schlegel) and Labrina No. 4. 3. Melanoph o res are seen on the body as well as on the oil globule ; the melanophores on the dorsal median line of the body arranged in a sing l e row......Stethojulis kalosoma (Bleeker), Thalassoma cupido (Temmincket Schlegel), Leptoscarus japonicus (Cuvier et Velenciennes) and Labrina No. 5-9. 4. Resembling to the previous group, but the melanophores on the dorsal median line of the body arranged in two or more rows......Duymaeria flagellifera (Cuvier et Valenciennes), Halichoeres tenui spinnis (Gunther), Callyodon ovifrons and Labrina Nos. 10-14. The egg of C. ovifrons is ellipsoidal in shape measuring 1.31-1.66 × 0.50-0.61 mm in diameter, having a single oil globule measuring 0.15-0.17 mm in diameter. Other features of the egg, egg development and hatched larva are much the same as those of other labrid fishes. As Winn and Bardach (1960 ) has pointed out the shape of the egg belonging to the family Scaridae, one of the two families of Labrina, is globular or ellipsoidal. It seemed that the egg is globular in the species belonging to the subfamily Sparisominae and ellipsoidal in the subfamily Callyodontinae.