Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/99

 AND AYES OF NORTH AMERICA. 93 Depth of glenoid cavity, Width ‘c CC CC 44 CC anterior expansion, CC CC fractured end, fn. 3.4 3.16 4.22 1.8 Another fragment of an animal of dimensions similar to the last was found at the same time and at or near the same place, (Freehold,) in Monmouth county, New Jersey, but cannot be associated with the aboie described scapula, as neither the place nor time of dis, covery can be ascertained with sufficient accuracy. It appeals to be the glenoid cavity of a scapula from which the blade has been broken off, and from which a short subtonic procoracoid projects. The accompanying cut and measurements will furnish the requisite information respecting it. Length from a to h, CC Cc b to c, CC CC tt to e, Ci CC e to f, Inches. 5.54 7.22 4.71 :3.53 Fig. 28. The fragment may belong to Mosasaurus. Pelvis.—There is much difficulty in determining the true relations of the pelvic ele-ments of these and other Dinosauria, owing to their unusual forms, our imperfect materials, and the discrepancies between authors Ilium.—One of our best clues is the skeleton of the Iguanodon discovered at Maid-stone, and preserved on a block of rag, which has been described and figured by Professor Owen. The bones mostly preserve a normal though much disturbed relation to each other. An examination o-f the figure and description strongly suggests First, that the hooked superior prolongation of the ilium is the posterior, not the au-terior, as described by Owen. This is confirmed by Owen's figure and description of the ilium and sacrum of the same species in Wealden Reptiles, Pl. III. (Iguanodon), where the thick hook-like process with its abrupt descent to the acetabulum, is also posterior. • The structure of Hadrosaurus, in which both caudal and lumbar vertebrae have been discovered, proves that this relation is the true one. The caudals have a greater trans-verse diameter than the Iambus, which are comparatively quite contracted from side to side. This is the reverse of what is usual among reptilia, where the caudals are usually AMERL PHILOSO. SOC.-VOL. XIV. 24