618 PROCEEDINGS OF THE NATIONAL MUSEUM. 



base; no spiracles; last j^ill -opening over the pectoral; first dorsal and 

 pectorals large, the dorsals nearer pectorals than ventrals; second 

 dorsal and anal small; a pit at the root of the caudal; caudal tin with 

 a single notch toward its tip, its lower lobe developed. One genus 

 with 5 species, inhabiting most warm seas. Large sharks, known at 

 once by the singular form of the head, which is not quite the same in i 

 any two species. 



15. SPHYRNA Rafinesque. 



Sphyma Rafinesque, Indice d'lttiol, Siciliana, 1810, p. 60 {zygxna). 



CcMrorhinns Bi.ainville, .Tourn. Phys., ISKi, !>. 284 {zyrjiena). 



Zyg;r)in CvviER, Rcgne Animal, Isted., 1817, ]>. 127 {zyr/Rma; name preoccupied i' 



in Insects). 

 PlntynqualuH Svvainson, Classn. Anim., II, 1839, ]>. 318 {''tiharo" =tudes). 

 Cestracion Klein (i)re-Linnaian) in (Jill, Ann. Lye. Nat. Hist. N. Y., VIII, 



1861, p. 412 {zyywmi). 

 Emplnjra Chi.i,, Ann. l.yc. Nat. Hist. N. Y., VIII, 1861, p. 412 {hlockii). 

 RnurrpH Gill, Ann. Lye. Nat. Hist. N. Y., VIII, 1861, p. 412 [tUnirv) . 



Characters of the genus included above. In the form of the head, 

 there is a perfect gradation among the species, from the narrow liam- 

 mer of 8. l)lochil^ with the lobes three times as long as broad and 

 deepl}^ grooved along the anterior edge, to the kidney-shaped head of 

 8. tihuro, in which the anterior grooves are obsolete. 



{ffdvpa. hammer.) 



Sphyrna: 



a. Nostril with a well-developed groove, which extends alonf>r the front of the 

 hammer-shaped head, the anterior and posterior outlines of which are nearly 

 parallel zygima, 17. 



17. SPHYRNA ZYGiENA (Linnaeus). 



SIIINOKUZAME (HAMMER SHARK): KASEBUKA (CROSS-HTAFF SHARK). 



Squalu.s zyypcna Linn.eus, Syst. Nat., 10th ed., 1758, p. 234; Europe, America. 



Cedracion zygwnn Dumeril, Elasmobranches, II, 1870, p. 382. 



Sphyrna zygsena Jordan and Gilbert, Synopsis, 1883, p. 25. — Jordan and Ever- 

 MANN, Fish. North and Mid. Am., I, 1896, p. 45; Cape Cod, Point Con- 

 ception. 



Squaleus malleus Risso, Ichth. Nice, 1810, p. 34; Nice. 



Zygxna malleus Schlegel, Fauna Japonica, 1847, p. 306, pi. cxxxviii; Naga- 

 saki.— Storer, Fish. Mass., 1867, p. 238.— GtJNTHER, Cat., VIII, 1870, p. 381.- 

 Nystro.m, Kong, Svensk, Vet. Ak., 1887, p. 49; Nagasaki. 



f Zygxna levdni'LoRD, in Griffith, Animal Kingdom, X, 1834, p. 640; Leeuwen, 

 Australia.. 



Zygxna subarcuata vStorer, Proc. Bost. Soc. Nat. Hist., 1848, p. 70; Cape Cod. 



Head truly hammer-shaped; width of head about twice its length; 

 length of hinder margin of hammer nearly equal to width near eye: 

 nostiil close to eye; prolonged into a groove w^hich runs along nearly 

 the whole front margin of head; first dorsal large; second quite small, 

 smaller than anal; pectoral rather large. Color gray. 



A large voracious shark, reaching a length of 15 feet or more, found 



