OCR Text |
Show 228 PROP. H. G. SEELEY ON THE [Mar. 21, The bones have a general resemblance in outline to the Plio-saurian type and to some Triassic Ichthyosaurs, but in neither is the pubic bone perforated. In the Trias of Europe the nearest parallel is found, perhaps, in the Neusticosauridse, though, according 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 P alceohattena, as indicated by Dr. 11. Broom, and this is as close as in Pliosaurus, but the pubis is notched on its hinder border, and not perforated as in Procolophon. The Stereosternum tumidvm of South Text-fig. 37. a, femur and tibia from tlie front; b, entire liind limb, posterior aspect; c, side view of the femur. America is the only genus which exactly parallels Procolophon in the pelvis. It is nearer than Mesosaurus. Neither 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 of Procolophon from Fernrocks is well shown |