ADDENDA 



.Some new material from the Niobrara beds of Kansas having come into 

 my possession since the preceding text was printed, I add some further 

 contributions to the knowledge of the fauna of that horizon. 



TESTUDINATA. 



TOXOCHELYS SERKIFER, Cope, S}>. HOV. 



This turtle is represented by bones of the cranium and of tlie carapace ; 

 the former including mandibular, maxillary, frontal, sphenoid, and quadrate 

 bones ; tlie latter, two lateral marginals. 



The dentary bone is stouter, but not so large as in T. latiremis, Cope, and 

 is flattened concave on its superior alveolar face, whose outer border, though 

 sharp, is not elevated above the level of the inner border. The symphysis 

 is short, and there is no beak. The inner face of the dentary is a broad, 

 shallow groove. The head has evidently been short and wide. The poste- 

 rior part of the maxillaries only are preserved. The alveolar face is flat, and 

 the outer border is produced vertically to a sharp edge. There is a suture 

 for a malar bone, and the orbit was evidently large. The frontal bones have 

 an open median groove below. The interorbital space is nearly flat, and the 

 or1:)ital borders subparallel for a short distance. The prefrontals are stout, 

 extend to tlie middle of the superciliary border, and are united on the median 

 line in front. The free border of the parietal on one side, though not well 

 preserved, indicates tliat the temporal fossa is partially roofed, as in Chelijdra. 

 The quadrate is remarkaijly solid, and is distinguished by the open or fissure- 

 like form of the meatus auditorius, which is a consequence of the shortness 

 of the posterior hook, which is not produced into contact with the lower part 

 of the body of the bone. The concavity of the upper part of it is very shal- 

 low ; its outline is subtriangular, with a flat superior border ; there is no 

 trace of the buUa-like superior chamber of Chelijdra. The body of the bone 

 is wide and slightly concave above, the anterior face separated from the supe- 

 rior by an overhanging angle, and also concave. The condyle of it is quite 

 small and flat; a larger, apparently articular, face is adjacent to it on the 

 posterior face. The sphenoid bone is wide and flat. 



299 



