MODES OF REPRODUCTION 333 



are especially characteristic of the coasts of California, but some 

 are also found on the shores of Japan. They are small fishes, 

 short and deep in shape of body, and allied to the Labridae or 

 wrasses of our coasts. It is a remarkable fact that viviparous 

 fishes are more abundant on the Pacific coast of North America 

 than anywhere else in the world, no less than 30 per cent, of 

 the fishes of this region, according to Eigenmann, exhibiting 

 this mode of reproduction. In addition to numerous species of 

 Embiotocidae, there are many bel®nging to the genus Sebas- 

 todes, one of the Scorpaenidae, to which family belongs also the 

 European viviparous form Sebastes norvegicus. This last 

 species is an inhabitant of the northern Atlantic : it occurs at 

 depths ranging to 100 fathoms along the west coasts of Sweden 

 and Norway, in the White Sea. off the coasts of Nova Zembla, 

 Spitzbergen, Iceland, Greenland and Newfoundland, and along 

 the American coast as far south as Cape Cod. Many other 

 species of Sebastes are known, but only norvegicus is viviparous. 

 This species has occasionally been taken on British coasts, 

 chiefly in Scotland, but in some cases it has been confounded 

 with another species, Scorpana dactyloptera, which is not vivi- 

 parous. Of the Blenniidae, in the restricted extent now given 

 to the family, only one genus is viviparous, namely Clinus, of 

 which several species occur off the coast of South Africa. 

 The so-called viviparous blenny of British and European 

 coasts, Zoarces vwiparus, is now placed in the separate family 

 Zoarcidae, allied to the Blennies. Of this family three other 

 genera are known to be viviparous, one of these being the 

 Cuban cave-fish Lucifuga. These cave-fishes of Cuba, Luci- 

 fuga and Stygicola are the only members of the family which 

 live in fresh water. It is curious that the cave fishes of Cuba 

 and those of Kentucky, although belonging to widely remote 

 families, should be alike viviparous. 



In viviparous fishes, as in other animals whose young develop 

 within the body of the mother, the two points of chief interest 

 are the modes in which, firstly, the nutrition and, secondly, the 

 respiration of the developing embryos are effected. It is 

 obvious that as the embryo has no direct contact with the ex- 

 ternal medium, oxygen must be obtained from the maternal 

 supplies. There is on the other hand no immediate necessity 

 for a change in the mode of nutrition. Embryos which develop 



