COPE.] PALEONTOLOGY LOUP FORK EPOCH. 519 



The most important paleontological results are, (1) the discovery that 

 the camels of this period possessed a lull series of upper incisor- teeth ; 

 (2) that the horses of the genus ProtoJiipptis are, like those of Hippothe- 

 ritim, three-toed ; (3) that a Mastodon of the M. oMotmis type existed 

 during the same period. 



List of species. 



CARNIVOEA. 



CANIS, Linn. 

 Canis, sp. incerta. 



Eepresented by a portion of the left ramus of the mandible, which con- 

 tains alveoli for, and portions of, I., 3 ; C, 1 ; and P. m., 4. The incisors 

 are closely crowded by the huge canines, which have larger proportions 

 than dogs generally, resembling more those of the bears, or large feline 

 carnivora. The first premolar is one-rooted, and separated by a long 

 diastema from the canine. The second premolar is two-rooted, and 

 separated from the first by a short diastema. The third is also separat- 

 ed by a diastema from the second, which exceeds that in front of the 

 latter. The fourth follows the third immediately. The mental foramina 

 are two, one large, below the first premolar, the other smaller, but lit- 

 tle below the alveolar margin, opposite the posterior margin of the sec- 

 ond premolar. 



Measurements. 



M. 



Length of fragment i... , 0.175 



Length from incisors toP. m. 4 .095 



Length of basis ofP. m. 3 .017 



Length of basis of P. m. 2 01 5 



Vertical diameter of canine at basis 029 



Length of symphysis , .075 



Depth of ramus at P. m. 2 047 



This large species is about as large as the Canis haydenii of Leidy, and 

 may be identical with it. It is characterized, among dogs, by the weak- 

 ness of its premolars as much as by the strength of its canines. 



Caniss^VUS, Leidy, Anc. Fauna Neb., p. 28. 



TOMARCTUS, Cope. 



Paleontological Bulletin, No. 14, p. 1. 



Established on a mandibular ramus, supporting a perfect carnassial 

 tooth and fangs of the following dentition : 0., 1 ; M., 4 ; the last incom- 

 plete ; hence the number of posterior teeth unknown. The ramus is much 

 narrowed in front. The carnassial has an inner tubercle within and be- 

 hind the median lobe, and a large posterior heel supporting both inner 

 and outer tubercles. The succeeding tooth was wide. 



This genus is apparently one of the Canidce. The carnassial tooth is 

 identical with that of the genus Canis, but the existence of only two 

 l)remolars in advance of it is a feline rather than canine character. 

 The jaw diminishes rapidly in size anteriorly, and the fragment contains 

 part of the fang of a large canine tooth, whose crown, like that of the 

 two succeeding teeth, is broken off". The form was evidently a short- 

 faced type of dog, concerning which additional information -will bo 

 looked for with interest. 



