THE PORBEAGLE SHARK. 



29 



usually taken smaller. It is said to be sometimes used for food in the Hebrides. The mouth is 

 below the eyes, and the teeth are flat like a pavement, and form crushing smfaces adapted to 

 masticate the Crustacea upon which these fishes usually feed. It is not very prolific, producing about 

 a dozen young simultaneously in the month of November. The embryo is not attached in this species 

 to the body of the parent. The caudal fin is short, and its hinder margin is usually whitish ; the 

 colour of the body is a uniform grey, with small whitish spots above the lateral line. These spots 



SMOOTH: HOVXD. 



are most marked in young specimens. In this genus the second dorsal fin is not much smaller than 

 the first. There is always a nictitating membrane ; there are small spiracles behind the eyes ; and 

 there is no pit at the root of the tail. 



FAMILY IT. THE LAMXIDJE. 



The second family of Sharks (Lamnidce) has no nictitating membrane, and no spiracles, or only 

 minute foramina to repi'esent them. The gill-openings are usually wide. Dr. Giinther divides the 

 family into two sections : first, the Lamnina, which includes Lamna, Carcharodon, Odontaspis, and 

 Alopecias ; and secondly Selachina, which includes the genus Selache, and possibly the Portuguese 

 genus Pseudotriascis. 



The best known of the three species of Lamna is the Porbeagle Shark, sometimes called the 

 Beaumaris Shark (Lamna cornubica), which occurs on British coasts, in the Mediterranean and 



