CATALOGUE OF VERTEBRATES. 661 



ISOGOMPHODON, GUI. 



{Caroharias. Prionodon.) 

 1. limbatus, M. & H. Spotted-fin Shark. 



Teeth scarcely serrated, narrow in both jaws ; snout short and 

 pointed ; gill openings wide ; upper edge of pectorals four times 

 length of lower margin ; some black on fins. Tropical ; stray- 

 ing north. 



SOOLIODON, M. & H. 



(Squalus. Caroharias.) 

 S. terrse-novsB, Rich. Sharp-nosed Shark. 



Teeth flat and oblique, with points turned to right or left 

 away from center ; pectoral fins large ; ventrals small ; color 

 gray ; tail fin black edged. Size rather small. Newfoundland 

 to South America. 



Family SPHYRNID^. 



Haminerlieads. 



SPHYRNA, Raf. 



(Sq.ualus. Cestraciou, &c.) 

 S. tiburo, L. (Section Reniceps.) Shovel-head Shark. Bonnet-head. 



Head kidney shaped ; eyes far separated, with nostrils near ; 

 front margin of head a semicircle ; ashy color. Length, 3 to 6 feet. 

 " Professor Baird met with this species at Beesley's Point." 



S. zygaena, L. (Section Sphyma), [malleug, subarcuatus.) Hammerhead. 



Head more truly hammer shaped, width twice its length. 

 Common from Cape Cod southward. Size large. 



"Only occasional specimens of the 'hammerhead' are met 

 with along our coast, but this species is more usually seen than 

 the spiked dogfish." 



Family ALOPIIDiE. 



(Iiamnoidea in part.) 

 Thresher Sharhs. 



Body moderately elongate ; snout short ; teeth alike, flat, triangular, 

 not serrated ; the third upper tooth much smaller than rest ; no nicti- 



