Sl6 



CLASSIFICATION OF FISHES, ETC. 



irregularly 



lobed^ and - 



truncate at 



the tip ; the 



teeth are tri- 



cuspidate, 



having three 



points; 



dorsal fins 



placed very near the caudal, the first being generally 



behind the ventrals ; head much depressed and rather 



broad. 



S. canicula. Bloch, pi. 114. (fig. 96.) 



Cestracion Cuv. Head not depressed, irregularly 

 cylindrical ; eyes almost vertical, placed very near the 

 crown, which is marked by two ridges ; dorsal fins 

 two, each furnished with a spine placed in front ; 

 ventral fin placed between the two dorsals ; caudal 

 moderate, unequally forked ; mouth terminal ; ante- 

 rior teeth small, pointed, and crowded; posterior 

 teeth obtuse, tessellated. 



C. PhilHpii. (Vol. I. p. 147. fig. 17.) 



MusTELUs Raf. General form of Galeus, but with all the 

 teeth flat and tessellated, as in the Rays ; spiracles 

 very large ; under lobe of the caudal very short. 

 M. laevis Cuv. Yarrell, ii. p. 393. 



Spiraculated sharks, whose natural affinities are uncer- 

 taiUj and whose rank as suh-genera or aberrant species 

 has not been ascertained. 



Hexanchus Raf. "^ Spiracles two; branchial apertures 

 six on each side ; dorsal and anal fin single ; tail un- 

 equal, oblique." 



S. griseus Lac. 



Galeocerdo M. and H. "Teeth strongly serrated on the 

 exterior edge, finely on the interior ; spiracles small ; 



