BY C. W. DB VIS. 
125 
molars with a vertical groove posteriorly. Upper premolars 
unilobate with an internal ledge and intero-posterior cusp. 
Lower premolar unilobate, with an intero-posterior cusp. Size 
somewhat larger than M. magister. 
The types of the species are the maxillaries alone; there is at 
present no direct evidence showing that the mandibles are rightly 
associated with them. 
Dimensions. 
Maxillary. — Adult and adolescent : The first four cheek-teeth 
are in length 55'0 and 55-5 (2). The true molar series is 53-6 
and 61-5 (2); the last three molars 44*5 to 55-0 (4); the last two 
36-0 (1); the last 19-2 (1); the first three 41-3 (1); m. 2 , m. 3 from 
30-1 to 37-1 (5); p. 4 is from 11-0 to 12-3 (3;. The width of m. 3 
is from 11-7 to 13-6 (14). 
Young: The series mp. 4 , m. 1 , m. 2 is 40 '0 (1). 
Mandibular. — Adult and adolescent : The cheek series varies 
in length from 61-0 to 70-0 (2); the last three from 42-7 to 54-0 
(4). The first four cheek-teeth are 52*2 in length, the first 
two true molars from 26-8 to 29*6 (3); the last two from 
35- 5 to 39-5; the first three are 45-6 (1); m. 2 m. 3 are 35-2 (1); 
m. 1 12-0 and 12-5 (2); m. 2 from 16-9 to 17*4 (3); m. 3 from 17*5 
to 20-0 (8); m. 4 from 187 to 20-5; p. 4 from 8-0 to 10-0 (4). The 
width of m. 3 is from 8-9 to 12*6 (24). The anterior depth of the 
mandible varies from 24 - 6 to 46 - 2 (13); the posterior from 23*5 to 
36- 6; its thickness from 15*8 to 25*1 (27). The latter measure- 
ments much exceed the greatest amount of difference in living 
species, and clearly indicate a confusion of two distinct species, 
but the means of distinguishing these otherwise than by size are 
as yet wanting. 
Form. 
Maxil/ary. — P. 4 (PL xviii. fig. 8). Obovate with diameters 1 1 -0 
and 6-6. Crest oblique, parallel with the outer side, notched at 
anterior third. An intero-posterior cusp a, separated from the 
lobe apically by a notch, posteriorly by a broad groove descending 
half way to the base, is connected with the fore end of the crown 
