308 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 38. 



Although the Puerco and the Torrejon are usually assigned to the 

 Lower Tertiary, it is the present writer's opinion that Professor Cope 

 was righl when he put thorn in the Upper Cretaceous. 



The writer expresses here his obligations to the officers of the U. S. 

 National Museum for the privilege of studying and describing the 

 interesting materials above mentioned. 



Genus COMPSEMYS Leidy. 



The genus < 'ompst mys has hitherto been known from only the most 

 fragmentary materials and has had assigned to it a quite heterogene- 

 ous lot of species. Although the type is Leidy's Compsemys victa, of 

 the Upper Cretaceous, it was for a long time supposed to be best 

 represented by Cope's Oonrpscmys pUcatula, of the Upper Jurassic. 

 In The Fossil Turtles of North America, page 47, the present writer 

 removed the last-named species from Compsemys and assigned it to 

 Marsh's genu- Glyptops, a genus of Pleurosternidse. Some scant ma- 

 terials in the American Museum of Natural History, believed to 

 belong to Compsemys victa, led the writer to believe that the species 

 possessed no mesoplastron and that it belonged among the Derma- 

 temydidse. In 1909, Mr. -T. II. Gardner and Mr. J. W. Gidley dis- 

 covered in probably Puerco or Torrejon deposits, near Ojo Alamo, 

 New Mexico, materials representing the two new species of Compsemys 

 described below. These materials show plainly that the genus had a 

 very huge mesoplastron and that it belongs to the superfamily 

 Amphichelydia. The strong development of the axillary and the 

 inguinal buttresses seem to ally the species with the Baenidse, rather 

 than with the Pleurosternidse. The following definition of Compsemys 

 is therefore proposed : 



A genus of Baenidse. Plastron relatively small, with broad meso- 

 plastra which meet at the midline. Axillary and inguinal buttresses 

 rising above the lower ends of the costals; these buttresses wide 

 transversely to the body and shutting off ample sternal chambers. 

 Peripheral bones united to costals by jagged sutures. Neural bones 

 with the broader end forward. External surface of all the bones 

 ornamented with small circular pustular elevations. 



COMPSEMYS PARVA, new species. 



The specimen which forms the type of the present species was col- 

 lected by Messrs. ( rardnerand Gidley, at Ojo Alamo, San Juan County, 

 New Mexico. The catalogue number in the [J. S. National Museum 

 i- 6548. There is some doubt regarding the level at which the speci- 

 men was secured, but it is supposed that ii came from the beds above 

 the upper conglomerate; therefore above the dinosaur beds. 



The individual was a, small one. the length of the plastron having 

 probably not exceeded 120 mm. There are present the greater part 

 of both hypoplastra, a part of the right mesoplastron, a part each of 



