Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/57

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AND AVES OF NORTH AMERICA
53
Fig. 8. Fig. 9.
Fig. 10.

Pelvic Arch.

The shaft is flattened cylindric; much flattened nearest the proximal extremity. The latter is very oblique to the shaft and slightly convex near the proximal margin.

The end of the muzzle reserved, includes also the symphysis and parts of the rami of the mandible. The parts have been crushed together, and the ends of the teeth broken off. The alveoli of the two jaws incline at a narrow angle to each other, hence the teeth which alternate, cross each other near the middles of the crowns. The parts preserved appear to belong to the premaxillary bone, though no suture can be found, and the bony walls are so thin as to render their obliteration a probability. There is a keeled ridge along the middle line above, which is not continued to the margin of the bone. The form of the muzzle is narrow, the sides subparallel near the tip. which is elongate rounded. The mandibular symphysis, however, is not very elongate, as the rami are given off at three inches from the tip. The latter appear to have been quite slender from various small sections or pieces sent with the muzzle. The premaxillary border of 4 in. 7 lin. exhibits eight teeth, or their alveoli, of which the median two are close together, and not separated by any mandibulars. The sections of the teeth are round or oval, and their sizes are irregular probably on account of differing age, and degree of protrusion: the diameters at alveolar margin vary from 6 lines to 3. Their form is slender conic, or with the root slender fusiform, and the pulp cavity is small and median.

AMERI PHILOSO. SOC.-VOL. XIV. 14