new Family of Pleurodiran Turtles. 171 



superficial resemblance. Althougli all I know of the animal 

 is derived from Mr. liamsaj's description and figures, yet 

 I think that a few words as to its systematic position will 

 usefully supplement that interesting contribution. 



We may first assume that Carettochelys is a Pleurodiran. To 

 say nothing of its habitat (all Papuasian and Australian Chelo- 

 nians belonging to that division), the tendency of the neural 

 bones to disappear altogether and the numerous band-like 

 plates on the fore limbs are highly suggestive of such affinity. 

 By " head non-retractile " I understand the author to mean 

 that the animal is a Pleurodiran ; but not a word is said of the 

 attachment of the pelvis, and the absence of epidermic scutes 

 deprives us of the well-known criterion atiorded by the azygos 

 gular plate. Then we see that it differs from all recent 

 Chelonians (save the Trionychidse, from which it is well 

 distinguished, besides being a Pleurodiran, by the structure of 

 tlie plastron) by the absence of epidermic scutes on the shell. 

 It differs also from all freshwater turtles by the structure of 

 the limbs, which form regular paddles, as in the marine 

 turtles, and which have likewise only the two inner digits 

 clawed. Tiiis of course is mere adaptive similarity, and 

 implies no affinity whatever with the Chelonidffi. Although 

 Caretlochelys stands alone among recent non-Trionychoid 

 Chelonians in the absence of epidermic scutes, it agrees in this 

 respect with the Tertiary Cryptodiran genera Anostiruj Hal- 

 low., and jPse^«iu//-«o/«j/x-, Dollo*. And although the limbs of 

 the latter are still unknown we may provisionally, taking the 

 shell only into consideration, surmise that Carettochely.H holds 

 in the Pleurodiran series pretty nearly the place held by these 

 extinct types in the Cryptodiran series. Whatever this 

 hypothesis be worth, the new genus deserves to rank as the 

 type of a new family of Pleurodira, which may be charac- 

 terized as follows : — 



Carettoclielydidae. 



Limbs paddle-shaped, the anterior much elongate ; only 

 the first and second digits clawed. No epidermic scutes on 



• It is intentionally that I abstain from nientioaiug Apholidrmys, 

 Pomel (Arch. Sc. Phvs. et Nat. Geneve, iv. 1847, p. ;}28), referred by 

 Cope to the Eniydidae. I'oniel characterizes it as a Chelonian witli the 

 carapace of an Emys, but devoid of scales, and the plastron of a Trionyx. 

 The genus is afterwards referred by Gervais tn Trionyx. As it stands at 

 present, however, Apliolkleniys is hardly more than a nonicn nudum. 



12* 



