AND AVES OF NORTH AMERICA. 



69 



IV. Cervicals with a thick obtuse transverse ridge connecting parapophyses in place 

 oJ' hypapophyses. 



Large; cup quadrate. BOTTOSAURUS HARLANI. 



HOLOPS BREVISPINIS, Cope. 



Thoracosawue breviepinis Cope. Proceed. Acad. Nat. Sci., Phila., 1867, 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 lour caudal vertebras 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 cretaceous 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, Now Jersey. 



The last arc from an adult, while the more perfectly preserved is not fully grown, since the neural arches of many 

 of the dorsal vertebras 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 eaudals. The species is the smallest of the genus, and 

 will furnish reliable date; Cor the estimation of the dimensions of other extinct crocodilia. The vertebras are relatively 

 more slender than those of the Alligators, and the general proportions are more probably those of the T. neoeae- 

 sariensis and of the Gavials. This will give a basis of estimation for the head and tail, 



Length of cervical series, 

 " dorsal " 

 " lumbar " 

 " sacral " 



Incites. 



7.75 



15. 



0.25 



2.33 



Total body, 



Caudal series (part estimated), 



llca.d (estimated), 



Total, 



81.38 



35. 



18. 



C ft. 71 inches. 



Oerrii-al vertebras.- Characteristic of the two of these before us, is the deep concavity of the inferior aspect of the 

 centrum with only a, traoe of a keel, and the steep elevation of the same surface to the rim of the articular cup. The 

 'alter does not forma well defined ridge, but rather a plane, connecting the anterior extremities of the parapophyses, 

 which, in the sixth, supports two short accuminate hypapophyses. In both cervicalsthe 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 pal 'apophyses. The 

 neural spine is little elevated, compressed, its anterior margin subacute, and obliquely turned backwards to a 

 posterior apex. 



AME1U. PHILOSO. SO0. — VOL. XIV. 18 



