188 GENERATION. 



regard to size. If the vesiculae seminales were really such, we might 

 suppose that the testicles would be much less iu those animals that 

 have the ' vesiculae' than in those that have them not ; as a small body- 

 that is always secreting, is capable of secreting as much in twenty-four 

 hours as a much larger one is in five minutes 1 . 



The testes in all animals, so far as I know, are oval. One might 

 suppose that this shape would give an easier exit out of the abdomen ; 

 but the testes of fowls, <fcc, are of the same shape. 



Tunica Vaginalis Communis. 



In the adults of [mammalian] quadrupeds, the tunica vaginalis testis 

 communicates with the abdomen, but it keeps nearly the same size, 

 between the testes and abdomen, that it had in the foetus ; so that this 

 part of the canal does not increase in proportion with the lower end where 

 the testicle is, and with the abdomen. 



The origin of the spermatic arteries and veins of the ovaria are the same 

 in all animals, let the situation of the ovaria differ as much as possible. 

 The origin of the spermatic arteries and veins of the testes and of the 

 ovaria is the same in all animals. 



The spermatic vessels go out from the abdomen higher up in the 

 quadruped than in the human ; they pass under the peritonaeum along 

 the psoas muscles before they get to the lower part of the cavity of the 

 abdomen, so that any pressure upon this part makes it act like a valve. 



Of the Prostate Gland. 



I suspect that the prostate gland does not go round the urethra [in 

 the human subject], and that there is none of this gland upon the ante- 

 rior part [of the urethra]. The reason that I suspect this is, that I 

 have seen that gland twice 2 swelled and diseased, but none of the disease 

 was on the fore part. 



Fowls have no bags similar to what are called the ' vesiculae seminales,' 

 and one would naturally think that they had the greatest use for them, 

 because the cock treads the hen at once, without any previous prepara- 

 tion ; but as the semen must be ready secreted for such quick demands, 

 nature has enlarged the terminations of the ' vasa deferentia' in him. 

 This would seem to support [the opinion of] the use of these bags in 



1 [In the feline tribe, hyaena, civet, weazel-tribe, which have no ' vesiculae semi- 

 nales,' the testes are proportionally smaller than in some quadrupeds, boar, e.g., that 

 possess them.] 



3 [This must have been an observation made a great many years ago, as Hunter 

 must have seen many such cases afterwards. — Wm. Clift.] 



