FOSSIL ANTHROPOIDS FROM INDIA 23 
The wide differences in this measurement may be partly sexual, as Weiden- 
reich (1936, pl. XI) has recently shown in the mandibles of Sinanthropus. 
There are also wide differences in respect to the degree of thickness of the 
body of the mandible: this in the type of Dryopithecus fricke is remark- 
ably robust, in Ramapithecus cf. brevirostris very thin. 
The symphyseal region of the mandible is fully known in only a few 
forms (Dryopithecus fontani, Sivapithecus sivalensis, Ramapithecus cf. 
brevirostris), but the range of structural variation approximates that of 
recent anthropoids. 
The lower dental arch of Sivapithecus, so far as we have been able to 
reconstruct it, may be nearly matched in form among recent orangs. The 
lower dental arches of several of the other Siwalik genera will be discussed 
by Lewis in his forthcoming memoir. 
The crowns of the lower incisors in Dryomthecus fontani, as figured by 
Gaudry, were transversely narrower than those of recent apes (ex- 
cept the gibbons). They were indeed more like those of Pleomthecus and 
thus presumably more primitive. The lower incisors of some Indian an- 
thropoids, although known only from their roots and alveoli, may have had 
somewhat wider crowns than those of the European Dryopithecus fontani, 
because the lower molars, at least in Sivapithecus, are distinctly progressive 
toward the modern orang type. Very little is known of the crowns of the 
upper incisors, but in Sivamthecus sivalensis and Ramapithecus brevirostris 
they were apparently narrower transversely than in modern anthropoids. 
As to the upper canine tooth, the apparently most primitive known 
anthropoid type is that of the East African, lower Miocene genus Proconsul, 
as described by Hopwood. This is characterized by a nearly straight ver- 
tical tapering crown, deeply grooved in front, with an incipient internal 
cingulum and basal tubercle; the bladelike posterior edge cooperates with 
the high pointed buccal cusp of the anterior premolar to produce a combina- 
tion of blade and notch, which recalls the conditions in the carnassial teeth 
of recent carnivores. In modern male gorillas, the posterior portion of the 
upper canine crown almost forms a second lobe, separated by a basal 
groove from the anterior portion—a very specialized condition. 
In certain female orangs the upper canines have short crowns and in 
several ways suggest deciduous upper canines. The upper canines of the 
Indian anthropoids vary from an almost premolar-like crown, in the sup- 
posed female Srvamithecus sivalensis, to a large dagger-like crown, in the 
male type of Sivapithecus orientalis. The lower canines are relatively 
wider in the labio-lingual diameter than the upper canines and the height 
of the lower canine crown is usually less than that of the upper. 
The possession of large male canines and obliquely sloping anteroexternal 
faces on the lower anterior premolars are characteristically anthropoid char- 
acters, which are doubtless overemphasized in some modern anthropoids. 
We follow Remane (1927) and Woodward (1914) in supposing the ‘“‘fem- 
