86 OKOLOGICAL SURVEY OF TEXAS. 



first mohir is injured at its .anterior border, so that this point can not be 

 determined. Tlie internal faces of the columns are but little convex on 

 M. ii and iii, but more so in M. i. The anterior part of P. m. i. is straight, 

 as in the other species of the genus described in this report, and not in- 

 curved as in A. lama. The heel of the M. iii is more strongly incurved 

 than in the other species, and is more as in A. lama. 



The canines are robust and are recurved, with a sharp posterior edge 

 and obtuse front at the base. The incisors are of graduated lengths, and 

 are entirely procumbent; the cutting edges of the second and third have 

 a strongly concave emargination of the border. Whether this is charac- 

 teristic of the species, I do not know, but the crown of I. iii is more ex- 

 panded outwards than in the H. hesternus and A. lama. The dental 

 foramen enters opposite the base of the keel of the M. iii, and it is not slit 

 downwards as in A. lama. The mental foramen issues below the poste- 

 rior border of the canine, as in A. lama. 



Measurements . 



Mm. 



Total length of ramus with hicisors 292 



Length of symphysis 69 



Elevation of precondyl.ir notch above inferior border 118 



Length of ramus posterior to M. iii 72 



Depth of ramus at long diastema 22 



Depth of ramus at P. in. i 33 



Depth of ramus at heel of M. iii 51 



Length of crown of I. i , 14 



Length of crown of 1 . ii 20 



Length of crown of I . iii 17 



Width of crown of I. iii 9 



Length of dental series 93 



Length of grinding face of P. m . i 14 



Length of grinding face of M. i 20 



Length of grinding face of M. ii 24 



Width of crown of P. m. i . , posteriorly 5 



Width of crown of M. i. , posteriorly 13 



Width of crown of M . ii . , posteriorly 13 



In the A. vitaheriana we have the following measurements of the su- 

 perior molars; the inferior molars are unknown. Length of molar series 

 without M. iii., 69 mm.; length of base of P. m. i., 20 mm.; length of 

 grinding face of M. i. , 24 mm. As the length of the grinding face of 

 the P. m. i. exceeds that of the base, it can not be much shorter than that 

 of the M. i., so that the aggregate length of the two is at least 45 mm. 

 In tlie present species this dimension is 34 mm. 



The Ilolomeniscus maa-ocephalus approaches more closely the existing 

 lama than any other extinct species of North America. 



Rock Creek, near Tule Canyon; W. F. Cummins. 



