﻿4 ARKIV FÖR ZOOLOGI. BAND 4. N:0 3. 



of the larger species is only 95 7o of that of the smaller. 

 Rh. guentheri has a still narrower forehead so that the corre- 

 sponding percentage for the same according to Thomas' me- 

 asurements is only 87,8 ^/o. 



Rh. guentheri Rh. g. smithi Rh. nasoguttatus 

 Basal length 

 Greatest breadth 

 Nasals, length 

 Nasals, combined breadth 

 Interorbital (least) breadth oii 



frontals 

 Breadth of brain-case 

 Gnathion to junction of nasals 



and maxillary 

 Gnathion to orbit 

 Gnathion to front of alvoolus of p 2 

 Length of npper niolar series 



The upper molar series is rather long in the new species 

 as it greatly surpasses that of Rh. guentheri and is equal to 

 that of the larger subspecies Rh. g. sinithi. 



A comparison between the skull of the present species 

 and the figures of the skull of Rh. guentheri communicated 

 by Thomas (Proc. Zool. Soc. 1894 p. 324 & 325) reveal some 

 other important differences. The greatest length of the fron- 

 tals of Rh. guentheri measured on the top view of the skull 

 (1. c. p. 325) is contained twice in the distance between the 

 anterior end of the nasals and the suture between the parietal 

 and the occipital. But in the new species the length of the 

 frontals is by far not contained twice in the same distance. 



The great length of the frontals of the new species is 

 also proved by the fact that their length on top of the skull 

 is more than twice the distance between the anterior foramina 

 supraorbitalia, while, to judge from Thomas' figure (1. c. p. 

 325), the latter distance in Rh. guentheri is more than half 

 the length of the frontals. 



The premaxillaries of the new species are mucli more 

 closely j oined anteriorly than those of Rh. guentheri. The 

 fissure between them is in the former only 1 mm. but even 

 in the reduced figure of the latter the same dimension is more 

 than that. 



^ This is the zygomatic breadth but the greatest breadth across the 

 skull at the posterior wall of the orbit is 59,5. 



