138 



LOWER VERTEBRATES. 



The ALEPOCEPHALiDiE are fislies intermediate between the clupeoid and salmonoid 

 forms, agreeing with the former in the absence of the adif)Ose fin. They inhabit the 

 deep seas, being among the most widely distributed and characteristic of the Bassalian 

 types. They are blacli in color and of soft substance. About ten species are now 

 known. 



The Alepidosaueidje are deep-sea fishes of large size, remarkable for the great 

 size of their teeth. The body is elongate, and without scales ; the mouth is extremely 

 large, with rows of compressed teeth of unequal size, some of those on the lower jaw 

 and the palatines being fang-like. The dorsal fin is very long, covering almost the 

 whole of the back, and there is no adipose fin. 



These fishes are found in the deep waters of the Atlantic and Pacific, and in their 

 depths are probably not rare. Occasionally specimens are cast on shore by storms, 

 especially along the Pacific coast of North America, and about Cuba and the Madeira 

 Islands. It is not likely that they ever rise near the surface of their own accord, and 

 when they are forced to do so they are killed by the reduction of the pressure. 



Fia. 89,— Hyodoii oLosoUles, moon-eye, toothed herring. 



Every part of the body is so fragile that perfect specimens are very rare. The dorsal 

 fin is readily torn, the bones are very feebly ossified, and the ligaments connecting the 

 vertebra3 are very loose and extensible, so that the body can be considerably stretched. 

 " This loose connection of the jjarts of the body is found in numerous deep-sea fishes, 

 and is merely the consequence of their withdrawal from the pressure of the water to 

 which they arc exposed in the depths inhabited by them. When within the limits of 

 their natural haunts, the osseous, muscular, and fibrous parts of the body will have 

 that solidity which is required for the rapid and powerful movements of a jjredatory 

 fish. That the fishes of this genus {Alepidosaurus) belong to the most ferocious of 

 the class, is proved by their dentition and the contents of their stomach." ( Giinther.) 

 Dr. Giinther elsewhere observes that " from the stomach of one example have been 

 taken several octopods, crustaceans, ascidians, a young Brama, twelve young boar-fishes 

 ( Capros), a horse-mackerel, and one young of its own species." 



Four or five species are known, all belonging to the genus Plagiodus {Alepido- 

 saurus). The Atlantic species or lancet-fish, (P. ferox) has been frequently taken in 

 the Gulf Stream. Another species, P. borealis, locally known as the hand-saw fish, is 

 occasionally found on our Pacific coast, and still another, P. cescidaphcs, in Alaska. 



