PROCAMELUS 



IN the " Proceedings of the Academy of Natural Sciences of Philadelphia" 

 for 1886, on page 12, Dr. Leidy gave the names of Aitchenia major, 

 mcdius, and minimus, to fossils from Archer County, Florida, indicating three 

 species of cameloid animals. No characters were given save the length and 

 breadth of the astragalus. 



The largest of these three species belongs to the genus Procamelns, and 

 would therefore stand as Procamclus major Leidy, and it is quite probable that 

 the two other species also belong in the same genus, although in the absence 

 of teeth this cannot be positively asserted. 



The entire dental series of P. major is not present, there being no speci- 

 mens of the first premolars, upper incisors, or second lower premolars, and it 

 .is by no means easy to determine whether certain curved caniniform teeth are 

 canines or first premolars. The dentition, however, may be characterized as 

 follows : i. \, c. \, pm. \ , m. -|. The second and third molars are very similar 

 to those of P. robustus, the first molars, second and third premolars much 

 larger. Thus, taking the teeth which are actually present, plate xvii. figs. 

 6-10, the combined lengths of lower pm. 3 and 4 and m. 1,2, and 3 is 155 

 mm. in P. major and 145 mm. in P. robustus. The length of the lower tooth 

 line, composed of pm. 2 and m. I, 2, and 3, in Camelus dromedarius and C. 

 bactrianus is respectively 142 and 152 mm. There is more of a ridge on the 

 posterior internal edge of the first pillar of m. 3 in /'. major than in P. robustus, 

 while the middle pillar is externally less symmetrical, its posterior portion 

 tending to form an angle. The same differences also exist between this tooth 

 and the corresponding tooth of Camelus. The posterior extremity of m. is 

 more rounded in P. major than in P. robustus, and the outer edge of the third 

 pillar is convex instead of concave as in Camelus. The last lower premolar is 

 about the size of that of C. bactrianus and a little larger than that of C. drome- 

 darius. The upper premolars and molars of P. major, plate xvii. figs. 1-5, 

 have a well-developed cingulum, and this in some cases bears a good-sized 

 tubercle opposite the furrow dividing the two pillars of the molars. 



The identity of the species to which the names Atichenia medius and 

 minimus are applied cannot be regarded as definitely settled, for there are no 



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