SYSTEMATIC CATALOGUE OF FISHES. 35 



Family SPHYRNIDiE. The Hammer-headed Sharks. 



This family resembles the Galeidse, but has the head peculiarly modified 

 into a hammer-shaped organ, with the eyes widely separated; teeth small, oblique, 

 similar in the two jaws; spiracles absent; caudal with a notch toward its top and 

 with a well developed lower lobe. One genus, represented in warm seas in most 

 parts of the world. The young numerous and born alive. 



Genus SPHYRNA Rafinesque. Hammer-headed Sharks, 



These sharks are readily distinguishable by their peculiarly shaped heads, 

 which by lateral extension have become hammer-shaped or kidney-shaped, the 

 eyes being at the ends of the lateral processes. Teeth small, notched on outer 

 edge, obliquely set in jaws; first dorsal and pectoral fins large, second dorsal and 

 anal fins small. The two species which are found on the Atlantic coast and are 

 taken in North Carolina waters may be distinguished as follows: 



i. Head kidney-shaped, the anterior and lateral margins confluent; groove from nostril to 



front of head obsolete tiburo. 



ii. Head hammer-shaped, the anterior and posterior margins nearly parallel; nasal groove 

 conspicuous zygoena. 



(Sphyrna, hammer.) 



9. SPHYRNA TIBURO (Linnaeus). 

 "Bonnet-nosed Shark"; "Shovel-headed Shark"; Bonnet-headed Shark. 



Sqiialus tiburo Linnseus, Systema Naturae, ed. x, 234, 1758; America 



Renicepa tiburo, Yarrow, 1877, 217; Beaufort. 



Sphyrna tiburo, Jordan & Gilbert, 1879, 387; Beaufort. Jordan. 1886, 26; Beaufort. Jenkins, 1887, 84; Beau- 

 fort. Jordan & Evermann, 1896, 44, pi. v, fig. 19. Wilson, 1900, 355; Beaufort. Linton, 1905, 344; 

 Beaufort. 



Diagnosis. — Body slender, slightly compressed; head flattened, .16 total length to end 

 of tail, semi-circular in front, its width slightly less than length; mouth small, crescentic; first 

 dorsal very high, second dorsal smaller, produced behind; anal larger than second dorsal; pec- 

 torals large; ventrals moderate; upper caudal lobe long. Color: hght gray above, whitish 

 beneath, {tiburo, a Spanish name for shark.) — 



Fig. 5. BoxNET-HE.\DED Shark. Sphyrna tiburo. 



The bonnet-headed shark is abundant on the Atlantic coast of the United 

 States, and is common in the Beaufort region. It is much smaller than the 

 hammer-headed shark, rarely exceeding 5 feet. Specimens examined at Beau- 

 fort in summer had been feeding on crabs, shrimp, and other crustaceans. One 

 brought to the laboratory July 25, 1902, contained 8 young. 



