272 PROCEEDINGS OF THE -NATIQ-^^AL MUSEUM. vol.46. 



premolar is placed 65 mm. behind the symphysis, while in Merriam's 

 specimen, No. 20028, furnishing a shorter jaw, the same tooth seems 

 to be at a distance of 75 mm. from the symphysis. Merriam has 

 stated that the symphysis in Camelus is much longer than in Auchenia. 

 This depends, however, on the species. From the specimens at hand 

 it is found that in the Bactrian camel the length of the symphysis 

 equals about 26 per cent of the length from the incisive border to the 

 rear of the condyle; in Auchenia, 28 per cent; in the dromedary, 35 

 per cent. On the assumption that the symphysis of Cragin's species 

 was 125 mm. long, its length would be 23.5 per cent of the length of 

 the jaw. It is not improbable that the symphysis was really longer 

 than 125 mm. Judging from the drawmgs presented, Cope's Texas 

 specimen^ referred to Jiestemus, had a symphysis equal to 24 per cent 

 of the length of the jaw, estimated as in the other cases. In that jaw 

 the position of the canine and that of the mental foramen are as in 

 Cragin's type. That jaw was, however, shorter than the latter by 

 about 100 mm. Furthermore, the fourth premolar appears to be 

 much nearer to the symphysis than in the case of Cragin's type, 

 apparently only about 40 mm. distant. 



The teeth of the various specimens at hand which are supposed to 

 belong to C. Jiuerfanensis must be described. None furnishes the 

 last upper mcisor; but the left premaxilla (Plate 25, figs. 2-4) described 

 above contains the socket of this tooth. This has already been 

 described. Likewise, the only trace of the upper canine is shown on 

 that premaxilla, as already noted. 



In Cragin's type the fourth premolar of the right side and all the 

 molars are present and in excellent condition. On the left side little 

 is left of the teeth except the roots of the third and fourth premolars 

 and of the fu-st and second molars. (Plate 26, fig. 1 .) So far as may be 

 determined from the two roots of the third premolar, this tooth had 

 the size of the corresponding one in Merriam's specimen, referred to 

 C. hestemus. In the table below are given the measurements of the 

 upper cheek-teeth. The height of the crowns is given as an indica- 

 tion of the stage of wear; for as the teeth are worn down, the antero- 

 posterior diameter, here called the length, diminishes (except in the 

 case of the third premolar and the last molar), while the transverse 

 diameter increases. In these measurements the length of the crown 

 is taken along the middle of the width of the grmding surface, while 

 the width of the tooth is taken at the base and where greatest. The 

 length of the whole series and of the molar series is taken in a straight 

 ine, not along the curve. 



1 Geol. Surv. Texas, 4th Ann. Rep., 1892, pp. 71, 93, pi. 21, figs. 3, 4. 



