SEX AND AGE DETERMINATION 



(6) SEX DETERMINATION BY THE GONADS 



(The Testes and Ovary) 



By dissection it is possible to examine the primary organs of re- 

 productionthe testes of the male and the ovary of the female which 

 are located within the abdominal cavity. 



The specimen is laid on its back with the head forward. An opening 

 is made from the tip of the breast bone to the vent or under the lower 

 ribs on the left side. (This will not spoil the bird for table use.) 



The intestines are pushed aside, care being taken not to disturb the 

 organs and tissues fixed to the "small of the back," particularly the 

 kidneys. 



In the case of the male the testes will be found, close together, one 

 on the forward end of each kidney (fig. 30). In juvenile males the testes 

 are small, elongate 

 and kidney-coloured. 

 In adult males near 

 the breeding season 

 the testes are greatly 

 enl a r g e d, somewhat 

 translucent, and 

 creamy white in col- 

 our; they shrink in 

 size and become dark- 

 er in colour after the 

 breeding season. Cau- 

 tion: Do not mistake 

 for the testes, a pair 

 of small, flat, usually 

 yellowish bodies cap- 

 ping the kidney; these 

 are the adrenal glands. 



In the case of the female the ovary will be found on the forward 

 end of the bird's left kidney. (In most birds the right ovary is per- 

 manently atrophied and non-functional.) The ovary has the appearance 

 of a cluster of small spheres like a bunch of grapes (fig. 31). In adult 

 females near the breeding season these are much enlarged, and the ovi- 

 duct or tube down which the egg passes toward the vent is large, wavy 

 in outline, and whitish in colour. After the breeding season, the ovary 

 gradually atrophies and the oviduct becomes small and difficult to trace. 

 In juvenile females the ovary is small, flattish and discoloured, but is 

 identifiable by its granular appearance. 



(The shell-less egg develops in the ovary glands and passes into the 

 oviduct, the shell being manufactured in the oviduct as the egg passes 

 through it.) 



Testes 



Spermatic 

 Ducts 



-Anus 

 FIG. 30. Testes and 

 ducts of male 



Ovaries 



Oviduct 



Anus 



FIG. 31. Ovary and ovi- 

 duct of female 



Gizzard; (H) Heart; (/) Intestine; 

 (K) Kidneys; (L)- Liver 



