28 



NATURAL HISTORY, 



THE HAMMER-HEADED SHARK.* 



The Hammei'-lieaded Shark differs from all others in having the sides of the head prolonged out- 

 ward in the form of a capital T. The eyes are placed at the extremities of these remarkable transverse 

 processes, and furnished with eyelids. The iris is of a bright golden yellow, with a black pupil. The 

 mouth is relatively small, has the semicircular form usual among Sharks, is placed on the under side 

 of the transverse expansion, and carries three, four, or five rows of triangular teeth, the rows becoming 

 in ore numerous with age. The cutting-edges of the teeth in this Shark are smooth in the young, but 



__ _^ ._ . __.,^ become serrated later 



in life. The teeth have 

 no barbs at the sides. 

 The nostrils open in 

 front of the head, and 

 are elongated. There 

 are five clefts for the 

 gills, which are at the 

 side of the body, and 

 placed between the 

 pectoral fins and the 

 hammer - like expan- 

 sion which carries the 

 eyes. This fish has 

 two dorsal fins ; the 

 anterior one is placed 

 over the space between 

 the pectoral and ven- 

 tral fins, and the hinder 

 one is over the anal 

 fin. The upper lobe 

 of the caudal fin is 

 long. The specimens 

 captured in British 

 seas are brown, on 



the back and paler on the under side, ten feet long, and measuring six feet in circumference. 

 They are said to weigh between six and seven hundred pounds. The body of a female contained 

 thirty-nine young ones, perfectly formed, each about nineteen inches long. The species frequents deep 

 water, and is said to be ferocious. It has been taken on the Cornish coast, at Tenby, and on the 

 coast of Norfolk. But its home appears to be in tropical and sub-tropical waters, since it is often met 

 with in the Mediterranean, round the shores of the Indian Ocean, in the seas between China and 

 Japan, and ranging southward through the Malay Archipelago as far as Sotith Australia. There are 

 in all five species known of this remarkable genus; and the other species occur in the Red Sea, 011 the 

 coasts of India, in the Gulf of Mexico, and tropical parts of the Atlantic, but they all appear to have 

 a wide range, and the Atlantic species has been met with in the Indian and Chinese Seas. Dr. Gunther 

 regards this genus as forming a second group of the Carchariidee, which he names Zygsenina. 



The third group in the family is Mustelina, from its type Mustelus. It comprises the genera 

 Trisenoclon, from the Indian Ocean ; Leptocarcharias, from South Africa ; Triads, from the Pacific 

 and Indian Oceans ; and Mustelus, which is represented by five species widely distributed in temperate 

 and tropical seas. 



THE SMOOTH HOUND, f 



The only British species of Mustelus ranges round the European coasts, and probably extends as 

 far as the United States. The name Smooth Hound refers .to the circumstance that the skin is 

 softer than the skins of other British Sharks. It grows to a length of about three feet, but is 



* Zyycena malleus. t Musteluf vulyaris. 



IIAMMEK-HEADED SHARK. 



