42 



MANUAL OF TAXIDERMY. 



testicles will be nearly or quite a half inch in dia- 

 meter, whereas in autumn they will not exceed a 

 number eight shot in size ; and in nestlings of the 

 same species they are not larger than a small pellet 

 of dust-shot. At this early age, the sex of birds 

 which have become somewhat soft is quite difficult 

 to determine, and the same is true at any season 



Fig. 6. 



if the specimens be badly shot up. There are 

 other organs, however, in the male. For example, 

 the sperm ducts are always present, appearing like 

 two white lines ; and in the breeding season the 

 plexus of nerves and arteries about the vent be- 

 comes swollen, forming two prominent tubercles 

 on either side (Fig. 6, 3, 3). 



In the female the ovaries lie on the right side 

 (Fig. 7, 2) in about the same position as is occupied 



