^36 CHONDROPTERYGII. RAT FAMILY. 



bable it may have belonged to the genus next to be 

 noticed. The discovery, however, by Dr. Johnson, 

 of a fresh and entire specimen on the shore at Spit- 

 tal, near Berwick, has removed all doubt on this 

 point. It was a small specimen, thirteen inches 

 long and twenty-one broad, the tail twenty-one 

 inches and a half in length. The synoptical charac- 

 ters given on a future page will convey a sufficient 

 notion of its appearance and peculiarities. It is ex- 

 tensively distributed, and examples have been found 

 measuring fifteen feet in length and weighing three 

 hundred pounds. It swims pretty rapidly with a 

 kind of sailing motion and little action of the pec- 

 toral fins, and, when taken, vibrates its tail violently ; 

 the first care of the fishermen is, therefore, to cut 

 off the caudal spine, which in a specimen approach- 

 ing the dimensions given above, is a very formidable 

 implement. 



Gen. CXXI. Cephaloptera. — The most con- 

 spicuous mark of difference between this and the 

 other spiny- tailed rays, is in the form of the head, 

 which is truncated anteriorly, and the pectorals, in- 

 stead of embracing it, are each prolonged consider- 

 ably in front, so as to present the appearance of two 

 horns. The species are very remarkable in other 

 respects, especially for the enormous dimensions 

 they sometimes attain. The Banksian Ray (belong- 

 ing to this genus) is said to have been found of such 

 weight that seven yoke of oxen were required to 

 draw it ashore. Voyagers speak of having seen 

 fishes of this genus swimming about their vessels, 



