No. 3.J 



PELVIS OF THE TESTUDINATA. 



349 



by the entoischia. In the Testudinidce, or true land tortoises, 

 I have never seen an ossified gastroid. The whole gastroid 

 cartilage may become absorbed by the pubes and ischia in adult 

 animals, and it may happen that all elements co-ossify. This 

 I have also seen in a very old 

 specimen of Clemmys guttata. 

 In half-grown Testudinidae the 

 gastroid cartilage is complete, 

 but entopubes and entoischia 

 are already united. 



E 



Fig. 6. 

 Testudo europcea, L. 



E, Epigastroid. 

 H, Hypogastroid. 



Fig. 7. — Trachemys elegans, Wied. 



E, Epigastroid. 

 M, Mesogastroid. 

 H, Hypogastroid. 



The pelvis of Platysternum, the only representative of the 

 Platysternidae, seems to be of the pattern of the Chelydridas, 

 I have no specimen at hand. Boulenger says : " The pelvis is 

 intermediate between that of typical Emydoids, in which the 

 pelvis and ischium are in contact on the median line, limiting 

 two obturator foramens, and that of Chelydra, in which the two 

 bones diverge, and are connected by ligament. In Platysternum 

 the symphyseal branches of the pubis and ischium are parallel, 

 but yet connected only by ligament. I must remark here that 

 the former type of pelvis, i.e. with two obturator foramens 

 separated by the union on the median line of the symphysial 

 branches of the pubis and ischium, occurs in all Testudinidae 

 (land and fresh-water) which I have examined, with the single 

 exception of Dermatemys, which belongs in this respect to the 

 Chelydroid type ; also in the Cinosternidae, but not in the 

 Staurotypidae, which belong to the latter type." ^ 



^ Boulenger, G. A. : Notes on the Osteology of the Genus Platysternum. Ann. 

 Mag. Nat. Hist., June, 1887, pp. 461-463, Pis. XVI, XVII. 



