FISHES OF WEST COAST OF PERU. 5 



In these individuals the anterior nasal valves are not acutely 

 pointed as stated by Regan and figured by Vaillant, but rounded. 



Genus SPHYRNA Rafinesque. 



8. SPHYRNA ZYGAENA (Linnaeus). 

 CRXTZ. 



Squalus zygaeno Linnaeus, Syst. Nat., ed. 10, 1758, p. 234 ; Europe ; America. 



Zygaena malleus Stoker, Fish. Mass., 1867, p. 238. 



Sphyrna sygaetia Jordan and Evermann, Fislies Nortli and Mid. Amer., vol. 



1, 1896, p. 45. — Gilbert and Starks, Fishes of Panama Bay, Mem. 



Cal. Acad. Sci., vol. 4, 1904, p. 13. — Starks, Fishes from Ecuador and 



Peru, Proc. U. S. Nat. Mus., vol. 30, 1906, p. 763 ; Callao, Peru. 

 fZygaena peruana Philippi, Ann. Univ. Chile, vol. 71, 1887, p. 545, pi. 2, 



fig. 2. 

 ? Sphyrna peruana Abbott, Marine Fishes Peru, Proc. Acad. Nat. Sci. Phila., 



1899, p. 328.— Delfin, Cat. Feces de Chile, 1901, p. 18. 



Tail and head, field Nos. 09510-11, of a hammerhead shark 100 

 cm. in length from Lobos de Tierra. 



The following dimensions of this individual were taken by Doctor 

 Coker : 



cm. 



Snout to origin of first dorsal 28 



Base of first dorsal 9 



Anterior margin of first dorsal 15 



Distance between first and second dorsals 24. 5 



Base of second dorsal . 3 



Anterior margin of second dorsal 4 



Second dorsal to tip of caudal 38. 5 



Distal lobe of caudal 30 



Anterior margin of ventral 4 



Anterior margin of pectoral 12 



Width of hammer 26. 5 



Eye to eye around snout 27. 5 



Antero-postero length of hammer 6-7.5 



Anal to tip of caudal 40 



Genus MUSTELUS Cuvier. 



KEY TO SPECIES. 



o\ First dorsal inserted anteriorly, the distance between origin of first dorsal 

 and tip of snout about six and two-thirds in total length. Teeth trans- 

 verse, with a low median keel mento, p. 6. 



a^ First dorsal situated farther caudad, the distance from tip of snout to 

 origin of first dorsal less than 4 in total length. 

 b\ Coloration variable; oblivaceous, flecked with white or dusky, with about 



15 darker crossbands; body robust, snout rather blunt ahbottup.G. 



&l Coloration plain olivaceous; head strongly depressed, body slender; snout 



pointed dorsalis, p. 7. 



b'. Coloration olivaceous, back and sides with black spots ; body robust, head 



not strongly depressed; snout blunt, thick nigromaculatus,i^.d. 



40656°— Bull. 95—17 2 



