BY C. W. DE 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. 



Dimeitsiojis. 



Maxillary. — Adult and adolescent : The first four cheek-teeth 

 are in length 55-0 and 55-5 (2). The true molar series is 53 -(3 

 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.'^ from 

 30-1 to 37-1 (5); p.^ is from 11-0 to 12-3 (3j. The width of m."^ 

 is from 11-7 to 13-6 (14). 



Young: The series mp.^, m.""^, m.^ is 40*0 (1). 



Ma.ndihular. — 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.- m.^ are 35-2 (1); 

 m.i 12-0 and 12-5 (2); m.^ from 16-9 to 17-4 (3); m.^ from 17-5 

 to 20-0 (8); m.^ from 18-7 to 20*5; p.'^ from 8-ato 10-0 (4). The 

 width of m.'*^ 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 difierence 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. „ 



Maxillary. — P. ^ (PI. xviii. fig. 8). Obovate with diameters 11-0 

 and Q-^. Crest oblique, parallel with the outer side, notched at 

 anterior third. An intero-posterior cusp a, separated from the 

 lobe apical ly by a notch, posteriorly by a broad groove descending 

 half way to the base, is connected with the fore end of the crown 



