72 GEOLOGICAL SURVFA'" OF TEXAS. 



Mm. Mm. 



Pli. Hoi. 



spatula, hcsternus. 



longitudinal 30 52 



Diameters I. ii J transverse at middle 17 19 



anteroposterior at middle. . 14 IG 



i longitudinal 25 39 



transverse at middle 22 12 



anteroposterior at middle. . 8 6 



i longitudinal 25 



anteroposterior 17 



transverse 12 



Diameters P. m. ii \ anteroposterior 23 



( transverse 10 



Diameters P. m.i (anteroposterior 29 27 



I transverse 13 16 



DiametersM.i (anteroposterior 35 38 



(transverse 22 19 



Diameters M. ii (anteroposterior 45 44 



( transverse 25 20 



Diameters M. iii J anteroposterior 65 56 



I transverse 24 16 



Depth ramus half way between C. and P. m. ii 52 42 



Depth ramus at front of M. iii 82 74 



Thickness ramus at end of M. iii 45 28 



As compared with the two species of Pliauchenia already described, 

 the much siipei'ior dimensions readily distinguish the P. spatula. It farther 

 differs from the larger of the two, the P. vulcanozum, Cope, in having the 

 premolar diastema at least double the length. This is, in fact, the largest 

 species of camel yet discovered, exceeding the Camelus dromedarius, L. , 

 and the Holomeniscus hesternus, Leidy, which agree in dimensions by one- 

 fourth. Prof. F. W. Cragin* has described a large lama from the late 

 Cenozoic of Colorado and Kansas, under the name of Auchenia huer- 

 fanensis, whose dimensions about equal those of the two species men- 

 tioned. According to Cragin, the dental formula is that of the genus 

 Auchenia. The last true molar is also represented to be smaller than the 

 penultimate, which is, if true, an exceptional character. I suspect, how- 

 ever, a typographical error. 



The relatively wider symphyseal region of the mandible also dis- 

 tinguishes this species at once from the Procamelus robustus, the Eblo- 

 meniscus hesternus, and the known camels and lamas. 



The mandible of the Holomeniscus hesternuslf above measured is from 

 Austin county, Texas, and has already been referred to by me in the 

 annual report of the Geological Survey of Texas, 1891, p. 251. It is the 

 best preserved specimen of this species yet obtained, and displays various 

 peculiarities. One of these is the procumbent and overlapping position 



*American Geologist, 1892, p. 257. 

 tPIate X, Figures 3, 4. 



