192 GIANT FISHES 



o. The head is normally formed. 



p. There is a pit at the root of the caudal fin. 

 q. There are no spiracles ; the teeth each 

 have a single strong, sharp point, 

 which may be smooth or with fine saw- 

 like edges . Blue Sharks (p. 36). 

 qq. Small spiracles are present ; the teeth are 

 large, flat, roughly sickle-shaped, with 

 a fluted edge, and with a triangular 

 point which is turned obliquely out- 

 wards . . . Tiger Shark (p. 42). 

 pp. There is no pit at the root of the caudal fin ; 

 the teeth are set obliquely in the jaws, 

 are notched, and have fine saw-like edges 



Topes (p. 45). 

 00. The sides of the head are more or less drawn 

 out into fleshy lobes, with the eyes at their 

 extremities, the head being kidney- or 

 hammer-shaped Hammer-head Sharks (p. 46). 

 dd. There is no anal fin. 



r. The body is not broad and depressed ; the 

 pectoral fins are normally shaped ; the first 

 dorsal fin is placed above or in front of the 

 pelvic fins, 

 s. The first dorsal fin is placed well in front of the 

 pelvic fins ; the spiracles are of moderate 

 size ; the skin is uniformly covered with tiny 

 denticles Greenland or Sleeper Shark (p. 48). 

 ss. The first dorsal jin is placed above the pelvic 

 fins ; the spiracles are minute ; the skin 

 has a number of scattered, round, flat, 

 button-like denticles, some of them with 

 tufts of small prickles 



Bramble or Spinous Shark (p. 51). 

 rr. The body is broad and depressed ; each pectoral 

 fin is prolonged forward to form a free angular 

 " shoulder " ; the first dorsal fin is placed well 

 behind the pelvic fins 



Angel-fishes or Monk-fishes (p. 53). 

 aa. The external gill-openings are on the under side of the 

 head, and are all below the base of the pectoral fin, 

 which extends forward above them ; the front edge 

 of each pectoral fin is joined to the side of the body 

 or head (Rays). 

 t. The pectoral fins are expanded, but are not com- 

 pletely united with the head and trunk to form a 

 flattened disc ; there is a strong, muscular tail, 

 with two dorsals and a caudal fin. 



