166 



CLASSIFICATION OF FISHES. 



Muller and Henle consider is so closely allied to Se- 

 lache, that they actually place them close together. 

 Finally, we quote the same authority for placing Sco- 

 liodon next to our Squalusj for, according to these 

 eminent naturalists, the one follows the other, and so 

 nearly coincide in their teeth, that those of Scoliodon 

 " diflPer only in being of the same shape in both jaws;" 

 — and thus we return to the point from whence we 

 commenced. 



(146.) "^^e now turn to the other column, composed 

 of the CentriiKB, having temporal spiracles. At the 

 head of these stands Cuvier's genus Centrina; under 

 which we place, as sub- genera, Spinaoc and Scymnus. 

 This latter, being aberrant, has no spines to the dorsal, 

 but, in the words of M. Cuvier, it has, in every other 

 respect, '''' all the characters of Centrina^ Scymnus 

 brings us immediately to the genus Galeus (Raf. Cuv.), 

 under which we may place Kotidanus Cuv., and perhaps 

 Etmopterus of Rafinesque, as uniting Scyjnnus, Galeus^ 

 and Centrina. Somniosus Le Sueur, from not having 

 an anal fin, seems to belong to the same group. And, 

 indeed, it almost seems that the next genus after Cen- 

 trina should consist of those sub-genera which have 

 neither dorsal spines nor anal fins ; in which case Galeus 

 will stand only as a sub-genus connecting Mustellus to 

 Centrina. We now arrive at that division which leads 

 to the Squalince; and we consequently find that some of 

 the sub-genera associated with Pristiurus Bon., as Scyl- 

 lium Cuv., and Chiloscyllium jM. and H., begin to have the 

 temporal orifices very small, so as to blend with Lamna, 

 and other subordinate forms in the circle we have just 

 left. In all these, as MM. Muller and Henle have well 

 observed, the first dorsal fin is never placed before the 

 abdominal fins. Cestracion, another genus with spined 

 dorsals, seems to follow the last ; and thus we arrive at 

 Mustelus, the affinitv of which with Centrina is mani- 

 fested in all but the teeth, which resemble those of the 

 saw-fish and skates. 



