308 CHONDROPTERYGII. SHARK FAMILY. 



caught in Berwick Bay, and it is not rare in the 

 Firth of Forth, where the fishermen often mistake 

 it for a full-grown example of the Common Dog- 

 fish. 



Gen. CIX. Mustelus. — The outline and general 

 aspect much the same as in Galeus, the disposition 

 of the fins similar, but the teeth are blunt and flat, 

 forming a closely compacted pavement on each 

 jaw. 



(Sp. 224.) M. Icems. Smooth Hound, Ray- 

 mouthed Dog, Smooth Shark. The skin of this fish 

 is much smoother and softer than that of sharks in 

 general ; it is from three to four feet in length ; and 

 is one of the kinds most frequently met with in the 

 British seas. When young, it is frequently spotted 

 above the lateral line, but these marks disappear in 

 the adolescent state. It is singular that such a de- 

 viation in the dentition from the general character 

 of the family should occur in a species, bearing in 

 other respects a perfect resemblance to the Tope and 

 others of the smaller sharks. In form and arrange- 

 ment the teeth are almost entirely like those of the 

 skate, and similar to those of pristis or the saw-fish. 

 " Hence we have supposed," says Mr. Swainson, 

 " that they are united by affinity, although there 

 appears a hiatus between mustelus and pristis which 

 nothing yet known is calculated to fill up." In re- 

 ference to the habits of the Smooth Hound, Mr. 

 Couch says that it keeps close to the bottom on clear 

 ground, where it feeds on crustaceous animals, which 

 * Cab. Cycl. Fishes, vol. i. 160. 



