ANALOGIES OF THE SQUALID^. ] 59 



Squalince, Centrince, Pristis, and Squatina or Crosso- 

 rhinus; the first and the two last forming the aberrant 

 group, while the second and third are considered as the 

 typical and the sub-typical. Let us place these in one 

 column, and the primary divisions of the Cartilagines 

 in another, and then trace their analogies. 



Analogies of the Squalid^ to the Cartilagines. 



Sub-families , , . 7 ri „„„. „ Families of the 



oftheSQL-ALiD*. Analogical Characters. Cartilagines. 



Squaiince. Dorsal fins generally without spines. Squalidje. 



n . . fOne acute spine on the first or se- } t , . „,_ 



Centring. J con d dorsal iins. {Raid*. 



Pristine. [ Sn ° U o? r S pSes ed ' ""^ *** prickleS } Chimajrid*. 



Crossorhince . Mouth furnished with cirri. Sturionid.£. 



Zyganirue. Kead or snout excessively broad. Polyodoxid^b. 



(141.) There is a somewhat intricate point, which the 

 last table brings more immediately before us, upon 

 which we must here say a few words. In the present 

 infant state of philosophic ichthyology, it is not likely 

 to claim that attention it will hereafter most assuredly 

 receive ; but we shall now advert to it, to show it has 

 not escaped our observation. This point regards the 

 rank of pre-eminence among the Squalidce. It may be 

 argued, that if the Raidce are typical of the order 

 Cartilagines, then it would seem to follow that the 

 Centrince) which clearly represent them, are also typical 

 of the Squalidce: both are distinguished by their spined 

 backs, which make them also analogous to the Aeon, 

 tkopteryges, the most typical of all the fishes. By re- 

 garding the Centring, therefore, in this light, we give to 

 all the groups we have just named one and the same 

 rank; that is, of being the pre-eminent types of their 

 own circles : nor does there appear any great objection to 

 this, if we only look to the groups just noticed. But 

 how would the case then stand, regarding the analogy 

 between the rays and birds ? for the latter are most cer- 

 tainly not the pre-eminent types of the Vertebrata, and 

 therefore the rank of these two would still remain dif- 



