248 



BULLETIN OF THE BUREAU OF FISHERIES. 







--7^^ 



Fig. 



-Denticles, Cetorhinus maximus, from Moutcrey, Cal. 

 no. 27024.) 



'■^mE: 



(U. S. National Museum 



Genus CETORHINnS Blainville. The basking sharks. 

 Cetorhinus maximus (Gunner). 



Cetorhinus maximus. Coles, 1914, p. 92. 



Teeth. — Teeth small, subconical, recurved, numerous, many-rowed, slightly compressed along 



lateral margins, back, of teeth 

 slightly more flattened tlian 

 the front, apex pointed ; teeth 

 arranged in regular rows, five 

 or six teeth in each row func- 

 tioning; numerous pockets 

 along outer margin of jaw 

 from which teeth have been 

 shed. 



Denticles. — The denticles 

 are small, unequal, suberect, 

 close-set, thomlike, with re- 

 ctuved tips; outer (anterior) 

 surface with a low, corrugated 

 median ridge which broadens 

 out at base with a slight 

 groove along each side on 

 apical portion; base large, cir- 

 cular, corrugated. (Descrip- 

 tion of teeth and denticles based on parts of a specimen in the United States National Museum, from 

 Monterey, Cal.) 



In July, 1905, Coles observed a huge shark lying motionless on the surface of the water out from 

 Cape Lookout. The size accredited to this specimen by Coles would indicate that it was the basking 

 shark, although no examples have ever been captured on this coast. 



Family ORECTOLOBID^. The nurse sharks. 

 Genus GINGLYMOSTOMA MUUer and Henle. 

 6. Ginglymostoma cirratum (Bonnaterre). 



Ginglyvwstoma cirratum. Coles. 1914, p. 89. 



Teeth. — Teeth in — rows, arranged in regular rows both transversely and laterally, about 9 teeth 



in a transverse row in front of upper jaw and 12 in the lower jaw; each tooth with a prominent, pointed, 

 median cusp and three smaller cusps on each side of it, base broad. At the sides of the jaw the cusps 

 are smaller, slightly curved toward angles of mouth; along anterior edge of the jaw the margin of each 

 tooth is practically smooth, cusps and denticles being worn away. (Description based on a set of jaws 

 of an adult from Pensacola, Fla., now in United States National Museum. 1 



In an example 26.7 cm. (10.5 inches) long from the American Museum of Natural History, col- 

 lected in Brazil, the teetli in the front of the mouth have a single cusp; behind these are tricuspid 

 teeth indicating that the form of the teeth changes considerably with age. 



Denticles. — The dermal denticles are large, being about 0.41 mm. long by 0.31 mm. broad in a speci- 

 men 26.7 cm. long, ovate, leaflike, quite regular in outline and arrangement and of nearly tmiform size; 

 sculpturing consists of a short distinct median keel extending along median line of basal half of denticle 

 and normally with a shorter lateral keel on each side, the latter sometimes absent; pedicel high, slender; 

 base short, broad, stellate. 



Coles observed a school of tliese sharks in Lookout Breakers in the summer of 1913 and succeeded 

 in captiu-ing one 273.3 '^^^- (9 feet) in lengtli. 



