306 CHONDROPTERYGII. SHARK FAMILY. 



spicuously distinguishes them from all other fishes. 

 The head is truncated anteriorly, and each of the 

 sides extended horizontally into a kind of branch, 

 which has the eyes at the outer extremity; the 

 latter thus appear placed on two thick peduncles. 

 Cuvier says that no other similar example is to be 

 found in the animal kingdom; but Mr. Swainson 

 well remarks, that a precisely similar arrangement 

 is observed in the small flies named Diopsis, in which 

 the eyes are supported on a pretty long peduncle. 

 Several species of Hammer Sharks have been de- 

 scribed, some of them even more remarkably pro- 

 duced at the sides of the head than the species below, 

 in particular Z. laticeps^ a native of the East Indian 

 seas. 



(Sp. 222.) Z. malleus. Hammer-headed Shark. 

 The earliest notice of this fish as British is to be 

 found in the Natural History of Yarmouth by C. J. 

 and James Paget, who state that an individual 

 was taken there in October 1829. According to 

 Mr. Yarrell, another example has been captured in 

 a herring net off the Monkstone Rocks, about two 

 miles to the west of Tenby. It is impossible to 

 mistake the genus Zygcena^ but as the several spe- 

 cies are very like each other and have not been pro- 

 perly discriminated till lately, it can scarcely be 

 assumed as certain that in the above instances the 

 fish was the true Z. malleus. It is, however, ex- 

 tremely likely, as it is by far the most common in 

 European seas. Its habits are very similar to those 

 of the other large sharks, and it shares with them 



