86 JOURNAL, BOMBAY NATURAL RIST. SOCIETY, Vol. XXVI. 



The changes in proportions transpiring with growth may be 

 tabulated as follows : — 



This table brings out two interesting facts. If firstly the figures 

 given for the southern specimens be compared with those of the 

 table at p. 82 it will be seen that the three largest stages are 

 represented by rats with tails either much longer or much shorter 

 relatively than those of equally grown individuals of the wild 

 girensis from the same district. That is to say, we meet with an 

 exactly similar departure from type in the dark bellied form of 

 this district as we do in the Central Provinces. Secondly the 

 northern dark bellied rats are distinguished irom both girensis and 

 the southern dark bellied specimens in every stage of growth by 

 their shorter tails. 



The skull is similar in both northern and southern dark bellied 

 rats and as regards size it aerrees with that of girensis. But it 

 presents characters which suggest that the dark bellied rat is the 

 indoor animal, living on a setter diet and therefore developing a 

 weaker set of jaw muscles than those of the outdoor, harder Jiving, 

 white bellied girensis. Thus the intertemporal distances are 

 increased (see Table II), both in relation to the condylo-basal 

 length and to the cranial width ; this increase indicates a diminish- 

 ed area of origin for the temporal muscles. The masseteric 

 plate is correspondingly a little narrower. The anterior palatal 

 foramina are as large as in girensis; while the palatal length is less 

 and the post-molar length greater — each of these two last dimen- 

 sions being relatively nearly as in Euiupean races. 



liemarks : — R. r. girensis is widely separated geographically 

 from all the other white bellied races of India. Although in 

 colour it closely lesembles narbadce it is quite satisfactorily distin- 

 guished from the latter b}- its cranial peculiarities and shorter 

 tail, and it undoubtedly deserves subspecific recognition. 



The dark bellied rats of Kathiawar are, in my opinion, plainly 

 indoor developments from girensis. The southern stock is already 

 quite clearly differentiated by its cranial characters and colour from 



