Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/86

 80 THE EXTINCT BATRACHIA, REPTILIA Several individuals of this, the largest of our cretaceous species, have been found, but only fragments preserved. The cranial bones are smoother than those of the species of Holops, and the posterior flares are separated as above mentioned. The cervical vertebra3 of this species are distinguished among those of its congeners by the lack of inferior concavity, breadth of basal carina, complete bifurcation of low bypapophyses, and posterior and transverse position of parapophyses. AMPHICOELIA. HYPOSAURIIS, Owen. Journ. Geol. Soc., London, V., 383. This genus is as yet the only known representative on this continent of the Amphi-coelian Crocodiles. It belongs, says Owen, to the Teleosauridae, from which the peat size of the parapophysis distinguishes it. Its remains ale quite abundant in the New Jersey cretaceous ; stratigraphically its position is the latest of its family. Thoraco-saurus being the earliest of the Procoelian Crocodilia, the interesting spectacle is pre-sented of the coexistence in America in large numbers, of two types which, in the old world, are separated by the whole period between the Jurassic and Tertiary. As might be supposed then, there is some approximation in structure between these two extreme genera of their series. The hypapophyses of the cervical vertebra in Thor-acosaurus are of the Teleosauroid type. Both ale. alike slender-nosed genera, as I have been able to ascertain for the first time for some of them. As a Teleosaurian reptile the bassioccipital does not present the vertical position usual among the Procoeli, but is horizontal. The sphenoid is also more horizontal in its expo-sure, and much wider, and with a straight anterior margin, not incised to accommodate the posterior nares. The frontal bone is marked with longitudinal shallow grooves. The teeth of Hyposaurus are more compressed than in the last genus described, some of them are from the shortening of the crown almost triangular in outline, but most are elongate; the enamel is thrown into a few fine continuous ridges. The cervicals may be distinguished from those of the other gavials of New Jersey, in addition to the form of the articular faces, by the earlier appearance of a strong keel-like hypapophysis, that is, on the fourth of the series; at first it is most prominent at the anterior end. HYPOSAURUS ROGERSII, Owen. Loc. Cit. Leidy, Cretaceous Reptile N. Am., p. 18, Tab. III, 4-21. rertebrir.-The neural spines of the cervical vertebrre are acuminate, of considerable—finally, of great—height, the anterior standing transversely on the neural arch, the median subtetragonal, the posterior, as usual, longitudinal in section. In an anterior cervical vertebra, length 2 in., the spine is 2 in. 10 1. above the ceiling of the arch, and is acute ; it receives a strong lateral wing from each posterior zygapophysis, which does not disappear till near the tip. These enclose a deep groove on each side behind, with a strictly perpendicular posterior median