SEXUAL CHARACTERS OF SOME DOMESTIC BIRDS. 



19 



pletely, even when in the elongated condition; though it frequently 

 happens that, owing to the extremely fragile nature of the testes, 

 they become broken. When this happens it is difficult to make sure 

 that all testicular material is removed ; that left behind is very apt to 

 grow. A second difficulty arises because of the relation of the sperma- 

 togenic portion of the testes to the ducts. The Wolffian body lies upon 

 the surface of the iliac and in intimate union with it. In removing the 

 testes from young birds this is usually left behind, and in some instances 

 it apparently develops independently of the spermatogenic portion. 

 In a few instances birds have been subjected to autopsy without 

 finding any trace of testicular material. Further work is required on 

 this point, since, naturally, these facts have been learned as the work 

 has progressed. 



TABLE 2. Orchidotomized male ducks. 



No. 1. This bird was over a year old when operated upon, August 8, 

 1909. He was in full summer plumage at the time. The left testis 

 was removed. A ligature was placed tightly about the base of the 

 right testis and this testis w r as allowed to remain. This bird did not 

 assume the summer plumage in 1910, 1911, 1912, 1913, or 1914. He was 

 killed in December 1914. No trace of testicular material could be found. 

 Traces, however, of the vas deferens w r ere found near its anterior end. 



No. 171. This bird, a few days after the operation, is shown in 

 plate vn, D, rear; hatched June 16, the testes were removed July 31, 

 1913. The protocol states that removal was complete but in fragments. 

 The laterals and scapulars were just beginning to appear. The history 

 of this bird was exactly that of a normal one to the time for the summer 

 molt. June 10, 1913, the bird was molting, but the new feathers were 

 exactly like the old, i.e., the bird did not develop the summer plumage 

 of the normal male. 



