594 Bulletin 47, United States National Museum. 



bladder none. Vertebrae about 50. A system of abdominal ribs symmet- 

 rically arranged along the wbole length of abdomen to front of anal fin. 

 Large fishes of the deep seas, found in the Atlantic and Pacific. Species 

 about 10, usually referred to 1 genus. Every part of the body is 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 

 vertebra) are very loose and extensible, so that the body may be consider- 

 ably 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 (Alepisaurus) belong to the 

 most ferocious of the class is proved by 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 can not be moved from the upper at a 

 greater angle than about 40." These fishes have never been taken in. the 

 deep-sea dredge or trawl. Most of the specimens known have been cast 

 up by storms or else taken on deep-sea lines. (Gunther.) (Scopelidce, 

 group Alepidosaurina, Giiuther, Cat., v, 420-423, 1864.) 



284. ALEPISAURUS, Lowe. 

 (LANCET FISHES.) 



Plagyodus* (STELLER MS.) PALLAS, Zoogr. Ross.-Asiat., in, 383, 1811, (nonbinomial), (sesaila- 



pius, no specific name.) 



Alepisaurus, LOWE, Proc. Zool. Soc. London, 1833, 104, (ferox). 

 Caulopus, GILL, Proc. Ac. Nat. Sci. Phila., 1862, 128, (altivelis). 

 Plagyodus, GUNTHER, Ann. Mag. Nat. Hist., 1867; after PALLAS. 

 Alepidosaurus, (corrected orthography). 



Characters of genus included above, (a, privative; Ae-xic; aavpb,Sauru8.) 



ALEPISAURUS : 



a. Ventral fins rather small, of 8 to 10 rays; dorsal rays 39 to 44. 



b. First ray of ventral serrated; pectorals elongate; dorsal rays 31 to 44. FEROX, 889. 

 bb. First ray of ventral not serrated; pectorals about 1^ in head; dorsal rays 36 to 39. 



JESCULAPIUS, 890. 

 CAULOPUS (/co.vA.6?, stem; TTOV'S, foot, the ventral of many rays): 



aa. Ventral fins rather large, of about 13 rays. 



c. Dorsal rays 40, the fin high; ventrals shorter than head. ALTIVELLS, 891. 

 cc. Dorsal rays about 34; ventrals as long as head. BOKEALIS, 892. 



d. Palatine teeth -well separated ; lower half of subopercle with coarse, radiating striae; 



only 2 or 3 ridges parallel with the posterior edge of the bone present. 

 dd. Palatine teeth close-set; lower half of subopercle for the most part with striae par- 

 allel with the posterior edge of the bone. SERUA, 893. 



*The name Plagyodns has been lately accepted by Dr. Gunther for this genus. A specimen of 

 one of the Pacific species was obtained by Steller from the Kurile Islands, and a brief description 

 of it, under the name of Plagyodus, left by him in manuscript, was afterwards quoted by Pallas, as a 

 species unknown to him. Steller wrote before Linnaeus, and apparently used the name Plagyodus 

 as a mononomial designation for his particular specimen or species, rather than in the sense of a 

 Linnasan genus. It seems to us, at present, best to retain the name Alepisaurus. 



