ANALOGIES OF THE MALACOPTERYGES. 235 



family of the Cartilagines that have cirri or barbels to 

 their mouth ; these appendages being more developed 

 among the Siluridce than in any other fish in existence. 

 The analogy of the Cobitidce to the cartilaginous fishes 

 has already been stated ; and although their direct rela- 

 tion to Prionodon is far less apparent than any of those 

 just noticed, still, if those are correct, it follows that 

 either this or some other extraordinary type will effect 

 the union. The Prionidcs, in fact, at present contain 

 only two fishes ; and it is yet undetermined whether 

 these, like all the other Cartilagines, are viviparous : the 

 probability is, that they really are so; and therefore even 

 one such character is quite sufficient to show some re- 

 lation to the Cobitidce. This point, however, must yet 

 be considered as debateable, until the real station of 

 Polypterus is more clearly determined than it now is. 



(211.) Lastly, it seems further desirable to test all 

 these relations, by tracing the analogies of the Mala- 

 copteryges with the Plectognathes, or cheloniform fishes : 

 the two circles, if placed in a linear series, will stand 

 thus : — 



Analogies of the Soft-finned and Cheloniform Fishes. 



Order of Annina-e« Order of the 



Malacopteryges. analogies. Plectognathes. 



SALMOxiDiE. The fins with soft rays. Balistid^; 



Pleuroxectidjs. Dorsal fins with spines. Chironectid^;. 



Gadid.e. Head broad ; mouth very wide. Lophid^e. 



Silurid^;. Body covered with mailed scales. Syngnathid^;.(?). 



Cobitid,e. Unknown. 



We have already adverted to the little diversity of 

 form — in comparison to what we see in the two typical 

 orders — that exists among the tortoise-formed group ; 

 and this fact at once accounts for their analogies being 

 less obvious than many others. Certain, however, it 

 is, that the Salmonidce are as typical of one order as 

 the Balistidce are of the other, or the Plectognathes : 

 the ugly aspect and unsymmetrical head of the Pleu- 

 ronectidte, again, find their representatives in the still 

 more hideous Chironectidce ; and both have fins with 



