Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/88

 82 THE EXTINCT BATRACHIA, REPTILIA Width of palate, ,Lines. 18.5 Height of os maxillare at middle, 14. Thickness of palatine suture of o. maxillare, 2.5 Cretaceous Green Sand of New jersey. Spec. nov. IIYPOSAURUS FItATERCULUS, Cope. This small species seems to be clearly indicated by a portion of the ramus mandibuli eontaining three and half a fourth alveoli, and two perfect teeth. These parts are less than half the size of those of the smaller individual of H. rogersi, whose maxillary bone and teeth are described iu the preceding article. The crowns of the teeth are shorter and more compressed than those in the corresponding part of the jaws in II. rogersi ; they are marked with a coarse obtuse fluting to near the tip, with a finely striate enamel as in Holops glyptodon ; in those of H. rogersi, the enamel is smooth and ridged by fine keels, which do not extend more than half the length of the crown. That the animal of which I describe this fragment was not the young of the larger Hyposanrus, is, I think, indicated by the deep grooving and strong ridging of the dense layer of bone of the ramus ; by the minute pulp cavity of the crowns of the teeth, and by the well developed successional tooth iu the fang of one of the latter, whose apex has nearly reached the alveolar margin. That the individual is not fully grown is probable, but that it is of smaller species than the H. rogersi, there appears to be little room for doubt. The ramus is scarcely flattened below, as is the case with most gavials, and the depth at the symphysis is equal the width of each minus. Sculpture in deep longitudinal grooves slightly inosenlating. Teeth directed very little outwards : their fangs and crowns are considerably compressed ; the a•tero-posterior cutting edge is stronger than the ridges, and does not diminish to the base of the crown. Viewed from within the form is symmetrical and straight ; from behind their crown is greatly incurved. The outline of the crown from within is an isosceles triangle, the width, more than .66 the height. Ribs on the inner face, seven, on the outer, eight. A few teeth in the jaws of H. rogersi are as short and broad as those here described, but they are not found in the middle of the series as in this species, but probably belong in the posterior alveoli, as occurs in some alligators. Lines. Length of fragment, 19.3 Width at middle, 6. No. of alveolae in an inch : three and half and interspace. Length tooth above alveolus, 4. erowu of tooth, 2.75 Width " " at base, 1.75 From the middle Green sand bed at Birmingham, Burlington, Co., N. J. Presented to the Academy by Judson C. Gaskill. INCERTAE SEDIS. The following species probably belongs to the Amphicoeli, but to what genus cannot well be determined, as nothing but the teeth are known. CROCODILUS HUMUS, Leidy. Trans. Amer., Phil., 1860, p. 146. Tab. Bad Lands of the Judith River, Nebraska.