16 SELACniI : SQUALL — IV. 



7. SPHYRNA Rafincsque. (An old name from o-^i'pa, 

 hammer.) 



a. Teeth in both jaws oblique, each with a notch on the outside near the base ; 

 no .ojiiracles. 

 b. Head truly hainnier-sliaped ; a long groove extending forward from 

 nostril;*. {Spfiyrnu.) 



9. S. zygaena (F..). Hammer-headed Siiakk. "Width of 

 "hammer" twice its length. Gra}'. L. 15 to '20 feet. All warm 

 seas, N. to Cape Cod. (^i«) (An old name from C'O"'''' * cross- 

 beam.) 



bb. Head kidne^'-shaped, the frontal groove obsolete. {Renireps, Gill.) 



10. S. tiburo (!>.). Bonnet-IIead Shark, Width of " ham- 

 mer " not nearly twice its length. Ashy gr'iv. L. 3 to 5 feet. 

 Warm seas, N. to Va. (^i"-) (^Tiburu, an Italian name of some 

 shark.) 



Family VII. GALEORHINID^. (The Typical Sharks.) 



Sharks with two dorsals and an anal fin ; no spines ; tail mod- 

 erate, not lunate, bent uj)wards, the fin notched below near the 

 tip ; basal lobe short; no caudal keel ; last gill opening above base 

 of pectoral ; eye with nictitating membrane; head normally formed. 

 Genera 15, species about 60, found in all seas. 



a. Teeth blunt, paved, without cusps or cutting edges; spiracles present; 

 no pit at root of tail ; labial folds about mouth. . . . Galkus, 8. 

 aa. Teeth more or les.s compressed, with sharp cutting edges. 

 b. Spiracles present ; teeth large; serrated. 



c. Root of tail with a pit above; caudal tin with two notches. 



Galeoceudo, 9. 

 bb. Spiracles none; teeth sharp; a pit at root of tail. 



d. Teeth all serrate in the adult CARCnARiiiNUS, 10. 



dd. Teeth all entire, all except the median ones obliijue; their points 



turned awny from the middle so that the inner margins are 

 nearly horizontal, and form a cutting edge. . Scoliouun, 11. 



8. QALETJB (Hafinesque) Leach. (Muslelus Cuvier.) 



(ya\f6i, shark; yaXtT), weasel.) 



a. Embryo not attached to uterus by a placenta; teeth very blunt. (Galeuf.) 



11. <S^. cania (Mitchill). Dor, Shark. Ilotxi) Shark. Boca 

 Dl'LCE. First dorsal higher than lon'j:, its middle midway between 

 pectorals and ventrals; snout shortish. Pale gray. L. .'i feet. 

 Smallest of our sharks. N. Atl.; common N. (/iu.) 



9. GALEOCERDO MilUer & Ilenle. (yaXf6t, .shark ; 



K€p8o), fox). 



12. O. maculatus (Ranzani). Tiger Shark. Brown, with 

 numerous large dark s])ot3. L. 10 feet. Warm seas ; rarely N. to 

 N. Y. (Lat., spotted.) 



