98 CALVIN P. STONE 



copulation. The submissive response of the female, as contrasted 

 with the vigorous response of the male, together with the inabil- 

 ity to perform the conjugal act on the latter caused the agressor 

 to relax his clasp and to dismount. 



The observations of Craig ('14) on the sexual behavior of the 

 dove reared in isolation bring oiuH; many interesting points con- 

 cerning the adequate stimuli for the initiation of the copulatory 

 act. Male doves, prior to sexual experience with female doves, 

 attempted to perform the sexual act upon the hand of the ob- 

 server. Copulatory attempts were made also upon such inani- 

 mate objects as the perch of the cage and the shoe of the obser- 

 ver. When placed with the receptive female very imperfect 

 coordination in mounting attempts were made prior to the suc- 

 cessful execution of the first complete act. One male mounted 

 obliquely across the body of the female and failed totally to effect 

 the union. Following the first series of successful consummations 

 of the sexual act a male showed marked alteration in his general 

 behavior, characterized chiefly by increased agressiveness. An 

 irregularity in the pattern of the copulatory act which persisted 

 for many months was noticed in the case of another male. The 

 preliminary billing that usually precedes copulation was entirely 

 omitted by this male. 



Kirkam ('13) studied the breeding habits of the rat. His 

 findings indicate that the male, though present at the tune of 

 parturition and for several days subsequently, does not kill the 

 offspring. One pair of young rats mated before either was sixty 

 days of age. This seems to be a very unusual instance of sexual 

 precocity. Observations on the copulatory action of brown rats 

 were reported by Miller ('11). He noted that the females in heat 

 did not allow the young males to copulate. Size and ability to 

 dominate were the determining factors. Frequently adult 

 females were seen chasing about the cage small males which 

 had attempted to copulate. When placed with an adult male 

 the same females permitted copulation, offering little or no re- 

 sistance. He concluded (from evidence that seems quite insuffi- 

 cient) that bodily odors served as a basis for sexual recognition. 



