CATALOGUE OF VERTEBRATES. 661 



ISOaOMPHODON, Gill. 



(Carcharias. Prionodon.) 

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



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

 pointed ; gill oi>enings wide ; upper edge of pectorals four times 

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

 ing north. 



SCOLIODON, M. & H. 



(Squalus. Carcharias.) 

 S. terrae-novse, 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^. 



Hammerheads. 



SPHYRNA, Raf. 



(Squalus. Cestracion, &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. zygsena, L. (Section Sphyrna), {malleus, suharcuatus.) 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. 



(Lamnoidea in part.) 

 Thresher Sharks. 



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

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



