PISCES. 67 



B. Squall jyrovided with anal Jin. 



t Dorsal fin single. 

 Notidanus Cuv. Temporal foramina small. Branchial apertures 

 six on each, side {Hexanchus Rafin.) or seven {Ileptanclms Rafin.). 

 Sp. Sqihalm cinereus Gm., from the Mediterranean Sea. 



ft With two dorsal fins. 

 a) With temporal foramina. 



Cestracion Cuv. Eyes without nictitating membrane. Spine in 

 front of both dorsal fins. Teeth crowded, anterior acuminate, 

 arranged in several rows, posterior flat, rhombic. Head flat above 

 or subconcave. 



Sp. Sqaalus PhiUppi ScHN. Port Jackson Sliarlc, Voyage of Governor 

 Phillip to Botany Bay. London, 1 789, 4to, figured opposite p. 383. The 

 teeth are figured in Cuv. R. Ani., ed. ill., Poiss. T15, fig. 3, and in OwEN 

 Odontogr. PI. 10, 11; Southern Ocean near New Holland, and a very similar 

 species on the coasts of Japan. The only representative of a numerous 

 group of fossil fishes, which lived principally in the coal-periods. 



Selache Cuv. Eyes without nictitating membi-ane. Teeth small, 

 conical, not serrate. Dorsal fins unarmed. Branchial apertures 

 large. 



Sp. Squalus maximus Guenner, Gmel., Blainv. Memoire sur le Squale 

 pelerin, Ann. du Mus. xViii. pp. 88 — 135, PL vi. 



Add genera Alojnas Rafin^, Odontaspis Agass., Lamna Cuv. 

 Temporal foramina small, sometimes very small, hence often over- 

 looked. Tail in S'qtiahis vidqyes Gm. (Alopias Rafin.) longer than 

 body exclusive of tail. 



Mustelus Cuv. Eyes furnished with nictitating membrane. 

 Teeth small, obtuse, rhombic, crowded. Dorsal fins unarmed, first 

 beginning above the termination of pectoral fins or at the posterior 

 margin of these ; second dorsal fin opposite the anal. Two poste- 

 rior branchial apertures above the pectoral fins. 



Sp. Squalus mustelus L., Miistelus phhejus Bonap., Faun. Ital. Tab. 

 132, fig. I, in the Mediterranean Sea and North Sea; the jaws with a 

 pavement of small teeth, as in many sharks ; a very similar species is dis- 

 tinguished by a yolk-sac placenta (see above, p. 41, note) during develop- 

 ment ; it is the Mustelus Ixevis Muell., the smooth shark, yaXebi Xeros of 

 Aristotelbs; see J. Mueller in the VerhandlungenderAkademieoi Berlin 

 for 1840 (Mustelus equestris Bonap., Faun. Ital. Tab. 132, fig. 3?). 



Triakis Muell. and Henle. 

 Thalassorhinus Valenc. 



5—2 



