•GONADS AS CONTROLLERS OF CHARACTERISTICS 147 



three attempting to suckle fern, male, remained so for forty-five minutes 

 changing position slightly if disturbed but immediately lying down again 

 with 3^oung searching around underneath. If young are displaced from 

 nest — mother immediately picks them up in mouth and returns them to 

 nest — fem. male not observed to return them to nest but allows them 

 to remain at the edge where placed. Normal male never seen in nest 

 with mother when latter is suckling. 



May 6, 2 p.m. Fem. male IV found on nest with young, on all fours 

 with abdomen arched and young attempting to suckle. Thought at 

 first was mother, reaction so characteristic, but examination showed 

 mother away from nest. Reaction could not have been different in 

 mother, so characteristic, no question whatever as to appearance of 

 same. Young of course could find no teats but were trying very hard. 

 Best and most conclusive reaction yet observed. 



3.30 p.m. Feminized males V and VIII removed from cage leaving 

 fem. male IV, normal male and mother. ]\Iother on nest: IV and 

 n/male in corner of cage opposite nest, n/male almost invariably 

 occupies this place and has never been seen to show any interest in 

 young. 



4.30 p.m. All three old rats in end opposite nest, young covered. 



5.30. All three old rats in end opposite nest, young covered. 



6.00. Same. 



8.00. Mother and IV on nest, young attempting to suckle both, both 

 removed from nest — n/male not near nest. 



8.30 p.m. Mother had covered young, all three old rats away from 

 nest. 



9.30 p.m. Fem. male (IV) on nest with all six young underneath 

 abdomen attempting to suckle, abdomen arched, legs spread, all 

 young searching for teats; absolutely normal female reaction. Mother 

 and n/male away from nest, IV removed from nest. 



May 7, 8 a.m. Mother in nest with three j'^oung suckling, IV in 

 opposite corner of cage attempting to suckle two young — nest had 

 been torn up during night and one young one nestling under n/male 

 but he showed no reaction to it and was only asleep. Placed all young 

 in nest with mother. 



11.00 a.m. IV and mother both on nest, mother suckling four 

 young, IV covering two. Norm, male in end opposite nest. IV taken 

 out of nest — five minutes later IV had returned to nest with mother 

 and young, n/male in opposite end of cage. IV again removed from 

 nest, and mother occupied it. 



11.45 a.m. Mother and IV on ne§t with young, one young under 

 IV, n/male in end opposite IV removed from nest. 



2.00 p.m. Mother suckling young, IV and n/male in opposite end 

 of cage. Mother removed from nest. 



2.40 p.m. IV on nest with young attempting to suckle, removed from 

 nest, n/male in end opposite. 



3.15 p.m. IV on nest with young, n/male in opposite corner of cage, 

 IV removed from nest. 



