264 



Records of the India 11 Museum. 

 II, — Observations Diadc at Belc^auiii. 



Vol. Ill 



I think that the following conclusions are justified by the 

 ligures : — 



(i) At Poona, mature female rats vary in weight from 50 to 

 190 gms., the mean weight being about [15 gms. 



(2) At Belgaum, they vary from 70 to 210 gms. with a mean 



of about 125 gms. 



(3) At both places, rats are more likely to bear five young at 



a time than any other number ; they may bear as few 

 as one or as many as ten (at Belgaum) or twelve (at 

 Poona). 



(4) At both places, rats which carry other than five young 



are more likely to have six young than any other num- 

 ber ; they are more likely to have six than four. TJiis 

 is remarkable ; it is, however, shown not only by the 

 aggregate figures but bv nearly all the separate arrays. 



(5) As regards their fertility the rats of Belgaum are some- 



what less variable than those of Poona. Not only is the 

 range of variation among the latter wider than among 

 the former, but rats of average fertility are more com- 

 mon at Belgaum than at Poona. If the values for fer- 

 tility be plotted in curves, that which represented the 

 Belgaum rats would be steeper but less wide than that 

 which represented the rats of Poona. Both curves 

 would be unsymmetrical in the same way 



(6) There is clear evidence that the largest and smallest vats 



are quite as fertile as those of average size. 



(7) There is no evidence that large rats are particularly fer- 



tile at Belgaum, or that small rats are particularly 



