40. ALEPIDOSAURID^ ALEPIDOSAURUS. 275 



the premaxillary, immovable. Teeth very unequal, immovable, and 

 subject to many variations in the same species ; a series of small teeth 

 the entire length of the preinaxillary ; those in front sometimes larger 

 and curved. Palatine teeth compressed, triangular, pointed; two or 

 three of the anterior ones exceedingly long and strong, fang-like; the 

 posterior ones moderate. Teeth of the lower jaw similar to those on the 

 palatines, one pair in front and two or three pairs in the middle being- 

 much enlarged. No teeth on the tongue. Eye large. Gill-openings 

 very wide; the gill-membranes not united, free from the isthmus. Gill- 

 rakers stiif, shortish, spine-like. Branchiostegals 5-7. Pseudobranehiae 

 large. Opercular bones thin, membranaceous. Dorsal fin very long, oc- 

 cupying nearly the whole of the back, of more than 40 rays; adipose fin 

 present, moderate; anal fin moderate; caudal fin forked. Air-bladder 

 none. Large ^shes of the deep seas, found in the Atlantic and Pacific. 

 One genus and 6 or 8 species. Every part of the Alepidosawrus+s so 

 fragile that it is extremely difficult to procure specimens. The structure 

 of the dorsal fin is so delicate that it must be liable to injury even in 

 the water; the bones are very feebly ossified, and the fibrous ligaments 

 connecting the vertebrae are very loose and extensible, so that the body 

 may be considerably stretched. "This loose connection of the single 

 parts 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 are 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 predatory fish. That fishes of this genus 

 (Alepidosaurus) belong to the most ferocious of the class is proved b}' 

 their dentition and the contents of their stomach, but it is worthy of 

 notice that although the mouth is so deeply cleft, the lower jaw cannot 

 be moved from the upper at a greater angle than about 40." (Giinther.) 

 (Scopelidcc, group Alepidosaurina Giiutlier, v, 420-423.) 



128. ALEPIDOSAURUS Lowe. 



Lancet- fislies. 

 (Alepisaurus Lowe, Proc. Zool. Soc. Loud. 1833, 104: type Alepisaurus ferox Lowe.) 



Characters of the genus included above. The name Plagyodus Steller 

 (Pallas, Zoogr. Eoss. Asiat, iii, 383) has been lately accepted by Dr. 

 Giiutlier for this genus. A specimen of one of the Pacific species was 

 obtained by Steller from the Kurile Islands, and a brief description of 



