On the development of the egg and prelarval stages of the puffer, Fugu (Shosaifugu) poecilonotus (Temminck et Schlegel)

Fugu (Shosaifugu) poecilonotus (Temminck et Schlegel) is a small puffer distributed through Japan, except Hokkaido, and southward. The author carried out the artificial insemination of this fish on April 10, 1954, at Nagato City, Yamaguchi Pref., and reared the hatched larvae for about 9 days in the glass jar. The spawning season seemed to extend from the beginning to the end of April there. The egg is demersal and strongly adhesive in nature, spherical in shape, measuring 1.11-1.28 mm in diameter with one cluster of small oil-globules each measuring 0.013-0.055 mm in diameter. The fundamental process of development is much the same with that of other teleost (Figs. B?M). During development big dendriate melanophores and reddish-yellow pigment cells appeared on the embryonal body and yolk surface, and also pale green pigment cells on the yolk surface. Hatching took place in about 12.5 days at the water temperature 13-16℃. Newly hatched larvae (M) measured 2.82\u27--3.08 mm in total length, with the myotome number 8+14=22. Rudimentary pectoral fins were already formed. Melanophores were distributed on the head, tail and yolk surface, but not on the back of trunk. Reddish-yellow pigment cells were found on the head, tail and on the yolk surface, and also pale green ones on the yolk surface. In 6 days, the larva (3.44 mm in total length) consumed all the yolk (0).コモンフグ Fugu (Shosaifugu) poecilonotus (Temminck et Schlegel)は本州北部から九州南部, 沖縄, マレーにかけて分布するやや小型のフグで, 全長250mmに達する. 筆者は1954年春, 山口県長門市仙崎町で2回に亘つて(4月10日, 4月21日)本魚の人工授精を行い. 両回とも孵化仔魚を得て約9日間飼育観察したので, 卵内発生と仔魚前期について報告する