Commercial Shark Fishing in the Caribbean Area 21 



d. Caudal fin about 1/2 as long as total length 

 of shark. 



Common Thresher, Alopias vulpinus, 

 Figure 37. 



e. Lower caudal lobe — Sharp-pointed and di- 

 rected rearward. 



Florida Dog Fish, Mustelus norrisi, 

 Figure 38. 



Mid-point of base of its first dorsal fin 

 much nearer to origin of pelvic fins than to 

 the- axil (armpit) of the pectorals. 

 Teeth low rounded without definite cusps. 

 Eyes without " winking" membrane. 



f. Lower caudal lohe — Broadly rounded. 



Common Smooth Dog Fish, Mustelus canis, 

 Figure 39. 



Mid-point of base of first dorsal about same 

 distance between pelvic fins and axil of pec- 

 toral. 



Its teeth low without definite cusps. 

 Eyes without "winking" membrane inside 

 lower eyelids. 



g. Dorsal fin — At least V2 of the base of first 

 dorsal fin is over pelvic fins. 



Cat Shark, Scyliorhinus torrei, Figure 40. 



h. Dorsal fin — Second dorsal fin almost as 

 large as first dorsal and anal fins. 



Lemon Shark, Negaprion brevirostris, 

 Figure 41. 



The middle of the base of the first dorsal 

 fin is as near to axil (armpit) of pectoral 

 fins as to the origin of pelvics or nearer. 



l. 



Teeth — Blade or awl-like (see Figure 42). 

 Only one or two in series function simul- 

 taneously; eyes have "winking" membrane 

 inside lower eyelids (see Figure 20). 



