APPENDIX 



Art. XXI. — Notice of some Extinct Testudinata • by 

 O. C. Marsh. (With Plates YII and VIII.) 



The remains of various Testudinata, some of sj)ecial inter 

 est, have recently been examined by the writer. A brief 

 description of a few of these is given below, and this, with the 

 figures on the accompanying plates, will make known their 

 main characters. Descriptions of other important specimens 

 of the same group will be given in later communications. 



Glyjytops ornatus, gen. et sp. nov. 



The present genus is represented by a number of charac- 

 teristic remains, among the most interesting of which is the 

 skull shown on Plate VII, figure 1, which may be considered 

 the type specimen. A striking feature of this skull is that its 

 entire external surface is elaborately sculptured. This charac- 

 ter, hitherto unknown in the Testudinata, has suggested the 

 name proposed. 



In its general features, this skull resembles that of Gkelydra 

 serpentina, Lin. It is wedge-shaped in form, when seen from 

 above, as shown in figure 1. The orbits are small, and well in 

 front. The nasal opening is directed upward, rather than for- 

 ward. The premaxillaries project downward in front into a 

 tooth-like beak. The nasals appear to be distinct. The max- 

 illaries are deeply grooved below, but show no indications of 

 true teeth. The skull is roofed over posteriorly, as in Chelone, 

 and some other sea-turtles. 



