152 



THE EXTINCT BATEACHIA, REPTILIA 



Lin. 

 16.25 



7.5 

 7.25 



11. 



10. 

 2.25 



13.75 



12. 



12. 



17. 



7. 



21.25 



25.5 



4.5 



6.25 



3.75 



Length of vertebral plate, 



" anterior suture plate, 



" " lateral suture plate, 



" posterior " " " 



" " suture, 



Diameter of neural canal, 

 Length of centrum vertebra, No. 2, 

 Width " behind diapophyses, 



" " at " 



Depth " with plate, anteriorly, 



Width of costal plate No. 1, 



" head of rib on No. 1 at origin, 

 Width costal plate, No. 3, 



It u it K 



Thickness of costal plate at 2.8.25 lines from prox. suture, 

 " second plate at rib on outer margin, 



" vertebral plate near margin, 



The costal plate of Trionyx, mentioned by Leidy (Cretaceous Reptiles, 113), from Burlington Co., N. J., proba- 

 bly pertains to the same species. Besides the localities above alluded to for the Tr. prisons, Leidy records a probably 

 third cretaceous species from I he Mississippi. The marine habitat of some of these species becomes quite probable, 

 for both individuals and species are perhaps too numerous for all to have wandered from the mouths of rivers. We 



pave the authority of Duchaillu for the statement thai, the Aspidoncefes aspilus is found, occasionally at sea, outside 

 the mouths of tin; rivers, where it occurs in tropical western Africa. 



TI! 1 OX V X CTTATITS. Leidy. 

 I'roo. Acad. Nat. Bci., Phila., 1869, p. 66. 

 Tertiary, at Church Buttcs, near Fort Bridger, Wyoming Territory, discovered by Dr. F. V. llayden. 



TRIONYX FOVEATUS, Leidy. 



Pr. A. N. B., 1860, p. 118. 



From the Upper Jurassic Bad Lands of the Judith Liver, Nebraska.. 



TRIONYX PENNATT7S, Cope. 



IV. A. N. Sci., 1H(!0, p. 12. 



This species is represented by the distal half or less of a- single costal bone. If Indicates a, large species of size 



similar to the Trionyx-priscus, Leidy, and of a, peculiar and handsome style of sculpture. The bone thickens distally, 

 and the margin is heavy and truncate, and rises abruptly above the free extremity of the rib propel-. The general 

 surface is plane; the structure consists of strong sulci, which are as wide as the intervening ribs, which diverge 

 slightly outwards on each side of a, narrow plane line, which extends on each side along the inter -costal suture. 

 Proximally, these grooves are continuous across the costal bone, forming a very open chevron, pointing outwards; 

 but they shorten, and are separated by a, triangular area of sub-round pits, which are not regular nor corres- 

 ponding with, the sulci; the latter shorten to the margin of the bone. The diameter of the pit is often smaller 

 than that of the sulci. 



