Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/74

 68 THE EXTINCT BATRACHIA, REPTILIA The lumbars grow widest as respect the centrum, to the sacrum. The two sacral vertebra; ale the broadest and most depressed and their cups and balls are flattened. The parapophyses rise fi mil the atlas till they stand truncated above by neurapophysial suture on the fifth dorsal. On the sixth dorsal they stand just above the suture, and on the seventh on a les el with anterior zygapophysis (II. brevispinis). Among modern Croc-odiles, Caimans and Gavials, Clavier found bypapophy:Nes on the anterior five or six dorsal vertebra ; on the Holopes and Thoracosaurus these processes are visible on the eighth, and probably on the ninth in II. brevispinis Cope. The teeth. in this genus are much curved. They have long conic crowns with minute lateral cutting edges and minute stria of the enamel, but no proper ridges as in Hypo-saurus. The teeth in T. neocaesariensis are blunter than in the others. In the H. glyptodon, the teeth are coarsely fluted, and the surface everywhere, finely and sharply striate. As the vertebra) of the species of this genus are very numerous, and the crania are usually much mutilated bane coining to the hands of students, I give a synopsis of their characters, including those of Thoracosaurus and Bottosaurus. I. Cervicals with deeply bifid hypapophyses, and transversely oval cup. Dorsals with transverse oval cups. T. NEOCAESARIENSIS. II. Cervicals with short united transverse hypophyses, slightly bifid. posteriorly ; anterior extremities more or less quadrate. Smallest species, vertebra l6 lines long (without ball) ; cups of all transverse oval. H. BREVISPINIS. Large ; dorsals about third and fifth, with subcordate outline and thin margins ; i. e, widened above, narrowed below, wider than deep; ceutra 20-25 lines ; cervicals with subquadrate cup. H. CORDATUS. Large, centia 2045 lines long ; dorsals about seventh, etc., much compressed ; cups deeper than wide, thild and fourth regularly round or oval, not cordate, with thick lips ; cups of cervicals round or transverse oval. H. OBSCURUS. III. Posterior cervicals with hvpapophyses scarcely traceable, and m ell separated. Large species ; dorsals near seventh, with transverse oval cup, with thick margins ; cups of cervicals subquadrate, bodies little keeled below ; ceutia 20-25 lines long. H. TENEBROSUS.