Page:The Osteology of the Reptiles.pdf/239

Rh Procolophon Owen, Saurosternon Huxley, Thelegnathus Broom, South Africa. Koiloskiosaurus Huene, Leptopleuron Owen (Telerpeton Mantell), Sclerosaurus Meyer, Europe.

. Skull triangular, broad behind, with long horns in tabular region and numerous conical protuberances. Orbits not elongate. Crowns of teeth denticulate. Intimate structure and skeleton unknown.

Elginia Newton, Scotland.

Primitive terrestrial reptiles with reduced dorsal vertebrae, expanded ribs, and an incomplete carapace of dermal bones.

The skull is doubtless wholly roofed over; the palatine is primitive, with numerous teeth. Maxillae and premaxillae with a single row of small teeth. External nares terminal. Vertebrae slender, notochordal, with vestigial spines; capitular attachment of ribs on anterior part of centrum, the second to ninth ribs with a vestigial tubercle, progressively broadened, contiguous at their borders. Pectoral and pelvic girdles primitive. Tail probably small. Femur slender, sigmoidally curved; feet unknown. Dorsal region strongly convex, covered with dermal ossifications, apparently in median and lateral rows.

This group at present is known by a single species, Eunotosaurus africanus Seeley, from the Middle Permian of South Africa, represented by incomplete specimens which have recently been described by Watson, from whom the above characters are taken. That the genus is intermediate between the true Cotylosauria and the Chelonia seems very probable, as Watson has urged. To locate it with either order will require many modifications in their definitions. For that reason it may be left in an independent position until further discoveries furnish more details regarding the skull, limbs, and carapace. The known characters ally it more closely with the Cotylosauria than with the Chelonia.

Middle Permian. Eunotosaurus Seeley, South Africa.