30 



FISHES OF NORTH CAROLINA. 



Family HEXANCHID^. The Cow Sharks. 



A small family of viviparous sharks, some of them of large size, character- 

 ized by 6 or 7 wide gill-slits and a single dorsal fin, together with a more or less 

 elongate body, depressed head, large and subinferior mouth without labial fold, 

 and teeth in upper j aw unlike those in lower. Two American genera, with 6 and 7 

 gill-openings respectively. 



Genus HEXANCHUS Rafinesque. Cow Sharks. 



In having 6 gill-openings, this genus differs from all other known sharks 

 with the exception of a deep-water form {Chlamydoselachus) from Japan and 

 Madeira. The teeth in the upper jaw consist of about 4 pointed ones in front, 

 3 on each side of these with 1 or many cusps, and lateral ones with numerous 

 cusps; the teeth in the lower jaw are a smajl median one with or without cusp 

 and lateral serrated ones with numerous cusps. Two species, one in the Atlantic, 

 the other in the Pacific. {Hexdnchus, six-slitted.) 



3. HEXANCHUS GRISEUS (Gmelin). 

 Cow Shark. 



Squalua griaeus Gmelin, Systema Naturae, 1495, 1788; Mediterranean. 

 Hexanchus griseus, Jordan & Evermann, 1896, 19, pi. ii, fig. 8. 



Diagnosis^ — ^Body deepest over pectorals, tapering gradually to base of caudal, greatest 

 depth less than length of head and about .16 total length to tip of caudal; head large, blunt; 

 mouth large, posterior angle extending nearly to first gill-opening; 2 teeth on each side of upper 

 jaw in front and curved outward, other teeth with 6 or more cusps; lateral teeth in lower jaw 

 with 7 to 9 cusps; eye small, placed far forward; snout short, nostrils near its tip; gill-slits 

 rather wide, anterior widest/ others progressively reduced; dorsal placed far backward, its 

 origin opposite posterior end of base of ventrals; anal siiftilar to dorsal but more posterior; 

 caudal stout, its length 1.5 times head; length of pectorals about equal to head to anterior gill- 

 slit. Color: dark gray, (griseus, gray.) 



Fig. 4. Cow Shark. Hexanchus griseus. 



The cow shark frequents the Mediterranean Sea and the west coast of 

 Europe, and is reported by Poey to be often taken about Cuba. There appears 

 to be only a single record of its occurrence on the coast of the United States. In 

 March, 1886, a specimen 10 feet 2 inches long was secured at the Currituck Inlet 

 life-saving station. North Carolina, and forwarded to the U. S. National Museum 

 by D. M. Etheridge; a plaster cast of the fish is now on exhibition. This shark 

 attains a length of 26 feet, and may always be readily distinguished from all 

 other species inhabiting our coast by the single dorsal fin and the 6 gill-openings. 



