850. 



RODENTIA 



defined, regular, about nine to the centimeter at middle ; length 

 of hairs equal to about one and one-half width of rings. Fur 

 soft but interspersed with numerous coarse hairs which impart 

 to it a somewhat harsh quality ; with a lens these coarse hairs 

 aie seen to be very slender bristles, distinctly grooved on the 

 upper side. Mammse : jj 2 — 2, i 3 — 3 = 10. 



Ciihnir. — The two main types of colour are (1) dark slaty, 

 becoming almost blackish on back, and (2) light brown above, 

 jiale buff or light grey below. All possible intermediate stages 

 exist connecting the two extremes. 



SlnJl. — In general featui'es the skull shows no marked 

 peculiarities. Dorsal profile faintly convex throughout, but 



Kir,. ITJ. 

 Jijiiinyx riiUiis. >'at. size 



flattened over posterioi' lialf of nasals, between orbits and on 

 posterior half of brain-case ; occiput squarely and almost perpen- 

 dicularly truncate ; ventral profile nearly flat. Brain-case squarish 

 in outline when viewed from above, but slightly longer than 

 wide and somewhat narrowed posteriorly, the sides of its upper 

 surface marked by conspicuous longitudinal ridges continuous 

 with the overhanging interorbital beads. The greatest width 

 of brain-case across these ridges is distinctly greater than length 

 cf parietal measured along ridge. No trace of sagittal crest, 

 but a low ridge-like lambdal crest present in old individuals and 



