12 PROCEEDINGS OF THE ACADEMY OF 



being like Crocodilus in cranial characters, while Thecacharapsa is a gavial. 

 The species of the latter are T. skkicodon Coite, abundant in New Jersey, at 

 Shiloh and elsewhere, with long curved cyliiidric teeth. T. sicaria Cope, 

 from Maryland, with much compressed crown of the tooth, with prominent 

 cutting edges. T. antiqua [Crocodilus Leidy,) with teeth less curved, cylindric 

 and with very short cutting ridges. From Virginia. 



The characters of the three species may be thus compared: 



The crowns of the teeth not compressed, with short cutting edges. 



T. a n t i q u a. 



Crowns cylindric, curved, with long and delicate cutting edges. 



T. s e r i c o d n. 



Crowns compressed with very prominent crenulate cutting edges, on a mar- 

 ginal base T. sicaria. 



The last named also possesses a large maxillary tooth, near the position of 

 the ninth of Crocodilus, which fits a corresponding concavity between two of 

 the mandibular teeth, resembling in this the existing genus Tomistoma. 



TESTUDINATA.' 



TRIONYX GeofiF. 

 Trionyx lima Cope, sp. nov. 



Represented by one costal-bone from Shiloh, N. Jersey. It is massive, and 

 strongly sculptured by numerous approximated narrow raised ridges, which 

 extend across the bone, with little inosculation, and which leave intervals 

 between them a little wider than themselves. 



The characters may be compared with those of the three species from the 

 cretaceous of New Jersey, as follows: 



Costal bone transversely figured by narrow elevated ridges T. 1 i m a. 



Costal bone with thick, low, transverse ridges, which are connected by cross- 

 ribs which leave series of pits T. p r i s c u s. 



Costal bones with transverse irregular grooves proximally which remain 

 along the sutures only distally, leaving an area of a shallow honey-comb pat- 

 tern medially T. p e n n a t u s. 



Costal bones with a shallow coarse honey-comb pattern, tending to conflu- 

 ence distally T. h a 1 p h 11 u s. 



April 6th. 

 The President, Dr. Hays, in the Chair. 



Twenty-six members present. 



The following papers were presented for publication : 



Notice of some Extinct Vertebrata from Wyoming and Dakota. 

 By Jos. Leidy, M. D. 



Description of new Crinoidea and Echinoidea from the Carboni- 

 ferous Rocks of the Western States, with a note on the Genus Oay- 

 chaster. By F. B. Meek and A. H. Worthen. 



Remarks on the Blastoidea with descriptions of ii-ew species. By 

 F. B. Meek and A. H. Worthen. 



The publication of the fifth number of the Proceedings for 1868, 

 was announced. 



April ISth. ^ ^ 



The President, Dr. Hays, in the Chair. 

 Twenty-two members present. 



[April, 



