日本近海に出現する浮游性魚卵-Xタラ目およびアンコウ目

抄録

The present paper, the tenth of the series of the pelagic fish eggs from Japanese waters, contains the figures and descriptions of 9 species belonging to the orders Gadida and Lophiida.
Gadida. The egg and larval development of Theragra chalcogramma (PALLAS) and Gadida Nos. 1-3 are known from Japanese waters. These eggs are globular in shape, 0.63-1.70 mm in diameter. The egg membrane is smooth, without any conspicuous structure, the yolk not segmented, the perivitelline space narrow. The oil globule is absent in T. chalcogramma (5-6 very small ones are present in early developmental stage, but they disappear during the develoment), or single one is present in Gadida Nos. 1-3. Only the melanophores appear in the egg and they are restricted on the embryonal body in T. chalcogramma, while melanophores and xanthophores appear on the embryonal body and oil globule in Gadida Nos. 1-3. The number of myotomes of the hatched larva is 35-50. The anus is situated the just behind the yolk, not reaching the fringe of the marginal fin, and it shifts forward during the larval development. The body surface is covered with granules.
Lophiida. The egg and larval development of Lophius litulon (JORDAN), Lohius sp., Pterophryne histrio (LINNÉ), Antennarius sp.and Agglutinated eeg No.2 (probably belonging to this order) are known from Japanese waters. Excepting Agglutinated egg No.2, these species spawn gelatinous egg veil. The egg veil of Lophiidae is long, nearly 5 m in length, but that of Antennariidae is rather short, less than 1 m in length and surface of the veil is covered with fine hexagonal mesh structure. The eggs of both family are imbedded in gelatinous substance in 1-3 layers, and 1-5 eggs are confined in a hexagonal or pentagonal compartment. The egg of Lophiidae is nearly globular in shape, 1.30-1.70 mm in diameter, containing a single oil globule measuring 0.33-0.35 mm in diameter. The egg of Antennariidae is ellipsoidal in shape, 0.62-0.98×0.52-0.70 mm in diameter, lacking the oil globule. The egg membrane of both family is thin (especially in early developmental stages), with out any conspicuous structure. The yolk is not segmented, but in Antennariidae hexagonal networks appear on the yolk surface as well as on the body and marginal fin at the late embryonic stage. The perivitelline space is narrow. Only the melanophores appear in the egg and larval development. The number of myotomes of the hatched larva is 18-32. In the hatched larva of Lophiidae dorsal and ventral fin rays appear before the comsumption of the yolk.
The eggs of Agglutinated egg No.2 are sticking to each other to form egg mass, without gelatinous substance. The number of the eggs of one mass seemed to be 5-10. The egg is nearly globular in shape, 0.70-0.74 mm in diameter, lacking oil globule. The egg and larval development are much the same as those of Antennariidae.