OSTEOLOGY OF THE NEW GDINEA TURTLE — WAITE, 117 



iStiiuiotypidfe and Cinosternid* developed." He also thought it 

 " probable that the Carettochelyidje are very close to the ancestors 

 of the Trionychia, of which they ai'e only survivals." When 

 examing the two imperfect skulls, previously referred to, 

 Boulenger found characters possessed only by Chely,^, among the 

 Pleurodira and by the Trionychidse. 



PVom the Pleurodira it is definitely excluded hy the following 

 characters : — 



The neck is bent in a vertical and not in a lateral plane ; the 

 cervical vertebriB do not possess transverse processes, and the 

 articulation between the centra of some of the posterior vertebne 

 is ginglymoid. The pelvis is not anchylosed to the carapace and 

 plastron. 



Vaillant placed Caj-eUochelys next to the Dermatem3'did{e in the 

 sub-tribe Phaneroderinea of the Euchelonina. 



Carettochelys has considerable affinity with the Cryptodira as 

 defined by Boulenger ; especially, as pointed out by Baur, with 

 the families Dermatemydidse, Htaurotypida?, and Kinosternid^e. 

 The difference as regards deep-seated chai-acters may be expressed 

 as that of the condition of the pterygoid bones. In CnrHtochdyx 

 they are widely separated by the palatines, basisphenoid and 

 basioccipital. In the cryptodiran chelonians, the pter3'goids are 

 in contact on the mid-line. The cervico-dorsal articulation is 

 cryptodiran, being, as I have shown, between the centra of the 

 vertebrpe, and not between the zygapophyses alone, as in the 

 Trionychoidea. On the other hand, the character of the pterygoids 

 and premaxillary associates CarettocJielys with the latter di\ision. 



It would seem therefore that, fundamentally, the Cryptodirans 

 and the Trionychoideans are related through CareUochdyn and its 

 fossil allies, and that the two divisions should not be separated, in 

 a linear arrangement, by the Pleurodirans. The features of this 

 reptile thus support the classification adopted in i-ecent revisions. 

 Want of an acquaintance with fossil forms, the absence of 

 specimens for comparison and the necessary literature, compel me 

 to abstain from a discussion of this subject. I trust, however, 

 that those who are qualified to weigh the facts adduced, will find 

 the data and illustrations supplied, useful in the elucidation of an 

 interesting problem. 



The whole characters of this Chelonian are not yet, by any 

 means, perfectly known, and further material will be necessarv 

 before the fourth and three succeeding vertebra?, the pelvis, and 

 caudal vertebrpe ca!i be described. We know nothing of the 

 shoulder-girdle and limb bones, and the number of plialanges in 

 the digits is still an uncertain quantity. 



