CENTRING. CESTRACION. 



147 



head, it will strike it, without piercing its own skin. 

 Its greatest size, however, seldom exceeds two feet. We 

 cannot subscribe to the supposition of M. Cuvier, that 

 Etmopterus aculeatus Raf. * is a typical example of 

 this genus ; for we know that the descriptions of this 

 author, as before remarked, were never taken from dried 

 specimens. The fifth of the most prominent divisions 

 of the spine-finned sharks is the sub-genus Cestracion 

 Cuv., which we have not yet seen. According to Mul- 

 ler and Henle, however, it has a prickle before each 

 dorsal fin ; a fact established by the figure given of the 

 Cest. Phillippii by Lesson (fig. 17«)> although not men- 



tioned, and perhaps overlooked, by Cuvier ; which is 

 somewhat singular, as he himself originally defined the 

 genus, t In addition to this, the teeth are tesselated, 

 - — those on the anterior rows alone, being small and 

 pointed ; while the mouth, unlike all the other sub- 

 genera of Centrina, is terminal, or at the extremity of 

 the pointed muzzle. The Cest. Phillippii is the only 

 species yet discovered : it is very rare, and inhabits the 

 coast of Australasia. It is not only analogous to 



* " Etmopterus aculeatus. All the fins and tail as if laciniated ; the 

 dorsal fins with a detached spine before each ; the posterior one almost 

 opposite the anal. — This is the smallest of all the sharks I have seen in 

 Sicily, for it scarcely exceeds a foot in length, and is the only one not 

 eaten. The fishermen distinguish it by the name of Diavolucchio de mari, 

 or little sea-deviL The snout is obtuse ; the nostrils are furnished with an 

 appendage ; the teeth small and acute ; the tail unequal and oblique ; and the 

 branchial apertures only three." — Raf. Caratt. p. 14. The Squalus vyatns 

 Raf, as Cuvier observes, is obviously a Spinax, but seems to me to differ 

 from our northern Spinax acanthias. 



+ With such conflicting statements as to simple matters of fact, as those 

 we have just been obliged to notice, it is almost impossible to determine 

 the limits of any one natural genus, or even of rigorously determining any 

 one point in the natural arrangement of this family. 



L 2 



