Manchester Memoirs, Vol. liv. (1909), No. *ii- 5 



season (March and early April) they may be heard to 

 squeak in the runs, and during this period I have re- 

 peatedly trapped them, bearing evidence of quite recent 

 coupling. Moreover, no one has ever recorded having 

 witnessed the act. 



One annual litter only. In my first paper* I have 

 gone fully into the question of the number of litters pro- 

 duced annually by a single female, and I will only 

 mention here that subsequent experience has fully 

 confirmed the evidence then adduced to the fact that only 

 one litter is produced per year. I have always found that 

 in any given season all the litters have been born within a 

 period of three weeks, and sometimes less, and as the 

 young remain four weeks in the nest, there would not be 

 time for two litters to be reared ; besides which, dissection 

 shows that neither male nor female is in condition to 

 continue breeding. 



Rate of groivtJi of the Young. In order to ascertain the 

 rate of growth of the young and the time they spend in the 

 nest I adopted the plan of taking one for measurement and 

 reference from each of several litters, and, after replacing 

 the nest as carefully as possible, repeating the process at 

 intervals of a few days. I found this quite practicable, and 

 it was an easy matter to calculate the daily increase and 

 to tabulate the result.f I was particularly lucky in finding 

 a litter that could only have been born the same day, of 

 which fact I was satisfied from the size (head and body 

 42 mm.), from the state of the remnant of the umbilical 

 cord, and from the extreme redness of the skin. I 

 have examined embryos, which were upon the point of 

 birth, measuring 37 mm., and allowing for those found in 



*"A Contribution to our knowledge of the '^loXe," Mem. and Pioc. 

 of the Manchester Lit. and Phil. Soc, vol. 47, Nu. 4. 

 tTableA,p. 8. 



