SEXUAL CHARACTERS OF SOME DOMESTIC BIRDS. 29 



July 16, 1915, in addition to organs similar to those of No. 1192, a 

 piece of tissue, 3 by 5 mm., was found attached to the mesentery, which 

 on sectioning proved to contain no spermatozoa or seminal tubules. 

 On the contrary, its structure was very similar to that of the same 

 material found in No. 1192. The possibility that this tissue is really 

 spermatogenic, but degenerate because of its age and its position on the 

 mesentery, can not at present be excluded, owing to the lack of suffi- 

 cient comparative material, particularly testes from normal old cocks. 

 Testes, however, from one old drake and one old cock have been 

 examined and found to be normal. The early history of No. 1177 

 is similar to that of No. 1192, but his later history differs slightly in 

 that his head furnishings grew to a larger size than those of No. 1192. 

 He also became more active and had much the bearing of the nor- 

 mal cock. 



In early maturity these two capons were not kept with hens, but 

 with cockerels. During the winter of 1912-13 they ran with hens along 

 with normal males. In March the normal males were removed ; shortly 

 after, the capons were observed treading the hens. They were never 

 seen chasing the hens, but when hens squatted on their approach 

 the capons mounted them and completed the sexual reaction. There 

 was no evidence of desire on the part of the capon, but his reactions to 

 the sight of the receptive hen indicate the existence of an instinctive 

 complex motor response to the specific visual stimulus. 



The mating reaction between normals strengthens the interpretation 

 given of the capon's behavior.. The psychological condition of each 

 of the principal actors is an important factor in determining the course 

 of the mating process. As a rule, the male is always ready to copulate. 

 The hens, however, vary. Some seem always ready, others never 

 ready, while others vary from time to time. If a hen is ready for copu- 

 lation she will squat and hold out her wings ready for the male to mount 

 whenever he approaches. Under such circumstances he will mount 

 the hen and complete the sexual act, even though as far as one can see 

 such intention was far from his mind. In other words, the action of 

 the hen starts a complex reflex. Such is what happens when a mating 

 occurs between the capon and hen; but in matings between normals 

 it often happens that the hen is not ready when the male approaches, 

 and if he attempts service she avoids him. If he is particularly 

 anxious for service he may chase her and eventually force service. This 

 sort of mating has not been observed on the part of the capons. Their 

 matings, on the other hand, so far as observed, have always been in 

 response to the female's solicitation. 



For surety's sake, a large number of the eggs of these hens were 

 examined, but all were found to be infertile. Later in the season, on 

 two or three occasions, the capons were seen crowing. The crow 

 was to all intents exactly the crow of a normal cock. This is inter- 



