The Two Components of Semen 21 



are subject to individual variations, which are particularly conspicu- 

 ous in man. But the storage capacity of the human vesicles is small 

 indeed in comparison with that of the bull or boar. In certain mam- 

 mals such as the dog or cat, the seminal vesicles are altogether 

 absent. In the rabbit, a combined anatomical and biochemical study 

 of the reproductive system has shown that the two organs known as 

 glandula seminalis and glandula vesicularis, develop from the same 

 diverticulum of the Wolffian duct, and possess a common urethral 

 outlet, so that both these glands together may be regarded as homo- 

 logous to the seminal vesicles proper of other mammals (Davies and 

 Mann, 1947«, b; Mann, 1947). 



Table 3. Composition of the boar seminal vesicle secretion 

 (m^./lOO ml.) 



(Analysis of 670 ml. seminal vesicle fluid representing the pooled 

 secretions collected from three boars; sp. g. 1046; pH 7-2.) 



