FISHES OF THE PHILIPPINE ISLANDS AND ADJACENT SEAS 211 



These expansions vary greatly from those species with only a slight 

 prominence to the extremes in which each lobe greatly exceeds the 

 length of the head. It is only with maturity such modifications are 

 found, for in the young they are less developed. All are voracious 

 feeders, usually living in deep water and some species reaching fif- 

 teen feet in length. A large female has been known to contain 

 upward of forty embryos. Fossils are known from the early 

 Tertiary. 



Genus SPHYRNA Rafinesque 



Spht/ma Rafinesque, Indice itt. siciliana, pp. 46, 60, 1810. (Type, Sqiialus zygacna 



Linnaeus, designated by Jordan and Gilbert, U. S. Nat. Mus. Bull. 16, p. 26, 



1883.) 

 Cestracion (Klein) Walbaum, Artedi Pise, vol. 3, p. 580, 1792. (Type, Squalus 



ziigaena Linnaeus, designated by Gill, Ann. Lyceum Nat. Hist. New York, 



vol. 8, p. 37, 1861, inadmissible.) 

 Sphyrnias Rafinesque, Analyse de la nature, p. 93, 1815. (Type, Squalus 



zygaena Linnaeus, virtually, as Sphyrnias Rafinesque proposed to replace 



Sphyrtm Rafinesque 1810.) 

 Cestrorhinus Blainville, Bull. Soc. Philomath. Paris, vol. 8, p. 121, 1816. (Type, 



Squalus zygnena Linnaeus, designated by Fowler, Geol. Surv. New Jersey, 



Bull. 4, p. 77, 1911.) 

 Zygaena (not Fabricius 1775 in Lepidoptera) Cuviek, Regne Animal vol. 2, 



p. 27, 1817. (Type, Squalus zygaena Linnaeus, tautotypic.) 

 Zygoena Risso, Hist. Nat. Europe merid., Poissons, vol. .3, p. 125, 1826. Type, 



Squalus zygaena Linnaeus.) 

 Zygana Swainson, Nat. Hist. Animals, vol. 2, p. 318, 1839. (Type, Zygaena 



laticeps Cantor, monotypic.) 

 Sphyrichthys Thienemann, Lehrb. Zool., p. 408, 1828. (Type, Squalus zygaena 



Linnaeus, virtually, as Sphyrichthys Thienemann proposed to replace 



Sphyrna Rafinesque.) 

 Platysqualus Swainson, Nat. Hist. Animals, vol. 2, p. 318, 1838. (Type, Squalus 



tiburo Linnaeus, monotypic.) 

 Sphyra Hoevbn, Handb. Dierk., vol. 2, p. 68, 1858. (Type, Squalus zygacna 



Linnaeus, virtually, as Sphy7-a Hoeven emendation for Sphynw Rafinesque.) 

 Eusphyra Gill, Ann. Lyceum Nat. Hist. New York, vol. 7, pp. 403, 412, 1862. 



(Type, Zygaena blochii Cuvier, monotypic.) 

 Reniccps Gill, Ann. Lyceum Nat. Hist. New York, vol. 7, pp. 403, 412, 1862. 



(Type, Squalus tiburo Linnaeus, orthotypic. ) 



Body behind head compressed. Head much depressed, with wide 

 oculonarial expansion at each side. Eyes remote from middle of 

 head, with nictitating membranes. Mouth inferior, greatly arched 

 forward, labial fold rudimentary. Teeth compressed, triangular, 

 bases broad, with cusps more or less obliquely directed toward mouth 

 angles and notched on outer edges. Nostrils at front edge of head. 

 No spiracles. First dorsal above space between pectorals and ven- 

 trals. Second dorsal above anal. Caudal with pits at origin, with 

 produced subcaudal lobe. 



