302 



FAUNA ANTIQUA SIVALENSIS. 



and comparative dimensions generally. The differences ob- 

 servable are slight. The symphysis is proportionally a little 

 deeper than in Entellus, and the height of the body of the 

 jaw somewhat greater. The chin, however, is considerably 

 more compressed laterally tinder the second molar than in the 

 Entellus, and the first molar is more elongated and sahent. So 

 much of the canine as remains has exactly the same form as 

 in the Entellus, and its proportional size is fully as great. As 

 shown by the dimensions, the jaw is much larger than in the 

 full-grown Entellus; in the former the length would have 

 been about 5*3 inches, while in the latter it is exactly 4 inches. 

 The fossil was a species of smaller size than the animal to 

 which the specimen described by Messrs. Baker and Durand 

 belonsfed, but less so than it exceeds the Entellus. 



Our limited means for comparison, restricted to two living 

 species, besides the imperfection of the fossil and the few 

 characters which it supplies, do not admit of affirmmg whether 

 it belongs to an existing or extinct species ; but the analogy 

 of the ascertained number of extinct species among the 

 Sewalik fossil mammalia makes it more probable that this 

 monkey is an extinct one than otherwise. There is no doubt 

 about its differing specifically from the two Indian species 

 with which we have compared it. 



The next specimen is shown in Plate XXIY. figs. 5 and 6. 

 It is a fragment of the body of the right side of the lower jaw 

 containuig the four rear molars. The teeth are beautifully 

 perfect. It had belonged to an adult although not an aged 

 animal, the last molar having the points a little worn, while 

 the anterior teeth are considerably so. The dimensions 

 taken along with age at once prove that it belonged to a 

 different and smaller species than the fossil first noticed. 



The dimensions are as follows : — 



The length of jaw, therefore, estimated from the space oc- 

 cupied by the teeth, would be 4 inches, while in the larger 

 fossil it is 5 '3 inches ; a difference much too great to be de- 

 pendent merely on varieties of one species. Besides, we have 

 another fragment, also belonging to the right side of the 



