206 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxx. 



The genus Sinopa has been held to include Stypolophiis and Proto- 

 tonuis of Cope, and until lately Limnocyon Marsh/' Wortman in 1902 

 showed that the type species of Limnocyon belongs to a distinct group 

 of the Creodonta, but referred L. «^f/?7/.s Marsh to Sinopa and described 

 the skull and parts of the skeleton from two finely preserved specimens. 

 The more complete material of S. rapax in the American Museum 

 collections, and the complete skeleton here described, show such con- 

 siderable differences from 8. agllis that it seems necessary to separate 

 them genericall}', splitting up the genus Sinopa into two closely allied 

 genera, each represented ])y a number of species in both Middle and 

 Lower Eocene. The generic distinctions are clear enough in the Middle 

 Eocene, but in the Lower Eocene the species are not clearly separable, 

 and most of them show various combinations of the characters of the 

 two groups. Sinopa rajxix Leidj^ is the type of the first, and Tritem- 

 nodtnt {Limnocyon) agilis Marsh will stand as type of the second group. 

 See figs. 1 and 2. 



DESCRIPTION OF THE SKELETON. 



The entire skeleton is preserved except one fore and one hind foot 

 and the distal half of the tail, of which only a few fragments remain. 

 Most of it is in remarkably fine preservation. As found in the rock, 

 the greater part of the vertebral column, pelvis, and most of the limbs 

 were articulated together; the skull and jaws and some limb oi- foot 

 bones were scattered; and several anterior dorsals and cervicals and 

 most of the ribs were scattered and more or less broken up and dam- 

 aged. The bones were very little crushed, and the articulations of 

 the vertebra? so perfect that the sequence of those found out of place 

 could be accurately determined. 



The skeleton compares for size and proportions with the civet. The 

 skull is elongate and rather large. The limbs are small and moderatel}'^ 

 slender, the neck of moderate length, the trunk long and slim, the tail 

 extremely long and powerful. The vertebral formula is C 7, D 13, 

 L 7, S 3, C ? 29. The fore and hind feet are five-toed, the digits rather 

 slender, not spreading, except the first, which is somewhat divergent 

 but not reduced in length. The scaphoid lunar and centrale are 

 separate. 



DENTITION, DEFINITION, AND SPECIFIC DISTINCTIONS. 



SINOPA GRANGERI, new species. 



Somewhat larger and more ro])ust than t*?. rapa.i-, with more massive 

 teeth and a diastema ))ehind P^. Skull about equal in size to Tritcm- 

 nodon agilis^ but shorter, considerabl}^ deeper in the facial rcgi(Mi. with 

 higher sagittal crest and deeper jaw. Premolars less compressed, 



«Cope, Scott 1892, Matthew 1901, 



