Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/75

AND AYES OF NORTH AMERICA. 69 IV. Cervicals with. a thick obtuse transverse ridge connecting parapophyses in place of hypapophyses. Large; cup quadrate. BOTTOSA US HA 'MAN . 1IOLOPS 1MEVISPINIS, Cope. Thoracosaurus brevispinis Cope. Proceed. Acad. Nat. Sci., Phila., 1807, p. 39. Geological Survey N. Jersey, Appendix C. The specimens on which this species are established are, a cervical vertebra in the Museum of the Academy of Natural Sciences, procured by Timothy A. Conrad at St. George's, Delaware, and one cervical, six dorsal, four lumbar, one sacral and four caudal vertebrae from the Greensand of Burlington County, N. J., which have been liberally placed at my disposal by the Burlington County Lyceum of Natural and Civil History. The last series is from the same individual apparently, and is more complete than that of any other eretaceous Crocodile hitherto brought to light. Also on a seventh dorsal, two lumbars and a humerus from the marl excavations of Samuel Engle, near Medford, Burlington County, New Jersey. The last are from an adult, while the more perfectly preserved is not fully grown, since the neural arches of many of the dorsal vertebrte have separated at their sutures, yet its approach to maturity is indicated by the persistence of this arch of the third cervical, of some dorsals, lumbars and caudals. The species is the smallest of the genus, and will furnish reliable date for the estimation of: the dimensions of other extinct crocodilia. The vertebrce are relatively more slender than those of the Alligators, and the general proportions are more probably those of the T. neocae- sariensis and of the Gavials. This will give a basis of estimation for the head and tail. Length of cervical series, It dorsal •‘ Inches. re 1•■■■ 1810 15. {< lumbar II 6.25 ,. sacral ., 2.33 Total body, 31.33 Caudal series (part estimated), 35. Head (estimated), 13. Total, 6 ft. 7} inches. Cervical rertebree.—Characteristic of the two of these before us, is the deep concavity of the inferior aspect of the centrum with only a trace of a keel, and the steep elevation of the same surface to the rim of the articular cup. The latter does not form a. well defined ridge, but rather a plane, connecting the anterior extremities of the parapophyses, which, in the sixth, supports two short accuminate hypripophyscs. In both cervicals the parapophyses look outwards at right angles to the centrum, but as in existing species, possess shorter articular surfaces on the third, whose body is also rather more elongate behind them. In the sixth, which will be typical of the posterior four of the series, from the crest of the posterior shoulder to the posterior outline of the parapophysis, is one-half the distance from the latter point to the margin of the anterior cup, and somewhat less than the articular face of the parapophysis. The posterior shoulder is elevated in both, and the articular globe is contracted and projecting. The vertical diameter of the neural canal of the third is four-fifths the same as the anterior cup. The latter is small, its vertical diameter being only double the depth of the osseous elevation between the parapophyses. The neural spine is little elevated, compressed, its anterior margin subacute, and obliquely turned backwards to a posterior apex. AMER'. PHILOSO. SOC.—COL. my. 18