GESTATION 



961 



TABLE m.l— Continued 



'- References. (1) Asdell, 1946. (2) Kenneth, 1947. (3) Deanesly and Warwick, 1939. (4) Farris, 1950. 

 (5) Rollins, Laben and Mead, 1956. (6) Norton, 1956. (7) Goy, Hoar and Young, 1957. (8) Arey, 1946. 

 (9) Selle, 1945. (10) Hartman, 1932. (11) Pearson and Enders, 1944. (12) Enders, 1952. (13) Svihia, 1932. 

 (14) Deanesly, 1943. (15) Deanesly, 1944. (16) Chitty, 1957. (17) Peacock and Rogers, 1959. 



*" Standard deviation. 



" Depends on the strain. 



'* Excluding the quiescent period. 



3l no. of litter 



-1^ 



Fig. 16.1. Decline in litter size with birth of 

 successive litters. • mean of 35 litters; EI mean 

 of 14 litters; A mean of 4 litters. (From D. L. 

 Ingram, A. M. Mandl and S. Zuckcinian. J. 

 Endocrinol., 17, 280, 1958.) 



1 2 3 4 5 6 7 8 9 10 11 



Serial no. of litter 



Fig. 16.2. Decline in number of fertile female 

 rats with birth of successive litters. (From D. L, 

 Ingram, A. M. Mandl and S. Zuckerman, J. En- 

 docrinol., 17, 280, 1958.) 



