294 FISHES. 



Nomcus, Corypli(Bna, Schedophilus, Seriola, Temnodon, Anten- 

 narius, Sternoiriycliidcn, Astronesthes, Exocoetus, Tetrodon, Dio- 

 don ; and only one genus of Sharks, Galeocerdo, approaches 

 the Arctic chicle. Some few sjjecies, like Antennarius, 

 Scopdus, are carried by currents near to the northern confines 

 of the temperate zones ; but such occurrences are accidental, 

 and these fishes must be regarded as entirely foreign to the 

 fauna of those latitudes. On the other hand, some Pelagic 

 fishes inha1)it the temperate zones, whilst their occurrence 

 within the tropics is very problematical ; thus, in the Atlan- 

 tic, Thalassorhinus, Selache, Lmmargus, Centrolojjhtis, Diana, 

 Ausonia, Zamjn'is (all genera composed of one or two species 

 only). Beside the Shark mentioned, no other Pelagic fishes 

 are known from the Arctic Ocean. 



We possess very little information about the Pelagic fish- 

 fauna of the Southern oceans. So much only is certain, 

 that the tropical forms gradually disappear ; but it would be 

 hazardous, in the present state of our knowledge, to state 

 even approximately, the limits of the southward range of a 

 single genus. Scarcely more is known about the appearance 

 of types peculiar to the Southern temperate zone ; for in- 

 stance, the gigantic Shark (Bhinodon), representing the 

 Northern Selache, near the coasts of South Africa, and the 

 Scombroid genus, Gastrochisma, in the South Pacific. 



The largest of marine fishes, Bhinodon, Selache, Carcharo- 

 don, Myiiohatida:, Thynnus, Xiphiida:, Orthagoriscus, belong to 

 the Pelagic Fauna. Young fishes are frequently found in 

 mid-ocean, which are the offspring of shore-fishes normally 

 depositing their spawn near the coast. The manner, in which 

 this fry passes into the open sea, is unknown ; for it has 

 not yet been ascertained whether it is carried by currents from 

 the place where it was deposited originally, or whether shore- 

 fishes sometimes spawn at a distance from the coast. We 

 may remember that shore-fishes inhabit not only coasts but 



