124 Bulletin American Museum of Natural History. [Vol. X, 



caviclus ca/iiii//s, as synonymous with the above, together with 

 Procami'lus a^ic^ustidens given by (^ope to various remains. It is 

 somewhat smaller than F. robustus, and is altogether intermediate 

 in size between this latter species and P. gracilis. It can be 

 readily distinguished from P. rohtistus by the coossification of the 

 two rami of the lower jaw at the mandibular symphysis, and 

 especially by the narrow lower molars. The first and secon.d 

 incisors disappear early in life and no traces of their alveoli are 

 seen in the adult skull. A large part of the skeleton is known, 

 and this is surprisingly like the modern genera. The two main 

 metapodials are firmly united into a cannon bone, and the ves- 

 tigial representatives of the two lateral metapodials are coossified 

 with them. No ungual phalanges, however, are known, and it is 

 a matter of uncertainty whether they were relatively high and 

 compressed like the early Camels, or whether they were broad 

 and depressed like those of the living camcliis. It is probable that 

 when found they will show the intermediate conditions between 

 these two extremes. Most of the skeleton has been described 

 and figured by Cope,' and need not be repeated liere. 



Procamelus gracilis Lcidy. 



The species, described by Cope under the name of P. fissidcns, 

 agrees in every particular, so far as the measurements are con- 

 cerned, with the above, and I therefore regard them as synony- 

 mous. P. gracilis is the smallest species of the genus, and its 

 remains are not uncommon in the Loup Fork Beds of Colorado 

 and Nebraska. It about equals the modern Llama in size, and is 

 considerably smaller than P. occidentalis. Of the materials in the 

 collection referable to this species, there are three lower jaws. 

 One of these has the posterior part of the symphysis preserved, 

 and this agrees with P. robustus and differs from P. occidentalis 

 in the lack of coossification of the rami, although the well-worn 

 teeth indicate an old animal. The lower molars are of the nar- 

 row type, in this respect agreeing with P. occidentalis rather than 

 P. robustus. In two of the specimens the second premolar is 

 well developed and two-rooted, but in the tliird specimen this 

 tooth is much reduced and single-rooted, thus indicating a ten- 



' Surv. W. looth M., p. 329. 



