228 



PROF. Hi a. SEELEY ON THE 



[Mar. SI, 



The bones have a general resemblance in outline to the Plio- 

 saurian type and to some Triassic Ichthyosaurs, bnt in neither is 

 the pubic bone perforated. In the Trias of Europe the nearest 

 parallel is found, perhaps, in the Nevisticosaurida?, though, accord- 

 ing to Yolz, the pubis and ischium in that type had no linear 

 contact as in the Pareiasauria. There is a general approximation 

 to the forms of the bones in the pelvis of Pcdceohatteria, as 

 indicated by Dr. R. Broom, and this is as close as in Pliosaurus, 

 but the pvibis is notched on its hinder border, and not per- 

 forated as in Procolophon. The Stereosternum tumidum of South 



Text-fia-. 37. 



Hind limbs of Procolophon, from Femrocks. 



a, femur and tibia from the front; b, entire bind limb, posterior aspect ; 

 c, side view of tbe femur. 



America is the only genus which exactly parallels Procolophon in 

 the pelvis. It is neai'er than Mesosaurus. ISTeithei' of these 

 genera admits of comparison in the occipital region of the skull. 

 But the pelvic identity of structure may justify the reception 

 within the Procolophonia of these allied types, although they 

 have been placed in distinct orders. 



Femur. — The femur oi Procolophon from Fernrocks is well shown 



