594 Bulletin 4J, United States iVational Museuvi. 



bladder uone. Veitebra' about 50. A system of abdomiual ribs symmet- 

 rically arranged along the whole length of abdomen to front of anal tin. 

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

 about 10, usually referre<l to 1 gouus. Every part of the body is so fragile 

 that it is extremely dil'licult to iirocure specimens. The structure of the 

 dorsal fiu 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 deej)-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 (Alejnsauru-'i) belong to the 

 most ferocious of the class is j)roved 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. (Giinther.) {Scopelidw, 

 group Alvpidosaurinu, Giinther, Cat., v, 420-423, 1864.) 



284. ALEPISAURUS, Lowe. 



(Lancet Fishes.) 



Plagyodus* (Stellf.u MS.) Pallas, Zoogr. Roes.-Asiat., iii, 3)<3, 1811, (nonliinomial), {xsaila- 



piiis, no specific name.) 

 Alepisamus, LowE, Proc. Zool. Soc. London, 1833, 104, (ferox). 

 Caulopvs, Gill, Proc. Ac. Nat. Sci. Pbila., 1862, 128, (aUivelis). 

 Plagyodus, Gunthee, Ann. Mag. Nat. Hist., 1867; after Pallas. 

 Alepidosmmis, (corrected orthographj'). 



Characters of genus included above, (a, privative; aett'l^; aavpoc,Sanru8.) 



Alepisaukus : 

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



h. Fii'st ray of ventral serrated; pectorals elongate; dorsal rays 31 to 44. ferox, 889. 



U). First ray of ventral not serrated; pectorals about 1 J in head; dcirsal rays 36 to 39. 



iESCl'LAPIUS, 890. 



Caulopi'S ((fouAds, stem; ttOus, foot, the ventral of many rays): 

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



c. Dorsal rays 40, the fiu high; ventrals shorter than head. altivelis, 891. 



cc. Dorsal rays about 34; ventrals as long as head. boueali.-;, 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. seura, 893. 



*The name Plagyodus has been lately accepted by Dr. Giinther for this genu.s. A Bpecinien of 

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

 of it, under the name of Plagyodim, left by liiin in manuscriiit, was afterwards quoted by Pallas, as a 

 species unknown to him. Steller wrote before Linuiicus, and apparently used the name I'hujyodjts 

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

 Linntcau gouus. It seems to us, at present, best to retain the name Alepisaurus. 



