ON GENERATION. 183 



All these foramina are so close to one another that they seem 

 almost to meet in a single cavity, which, as being common to 

 the faeces and urine, may be called the cloaca. In this cavity, 

 the urine, as it descends from the kidneys, is mingled with the 

 feculent matters of the bowels, and the two are discharged 

 together. Through this, too, the egg, as it is laid, forces 

 itself a passage. 



Now, the arrangements in this cavity are such, that both 

 excrements descending into a common sac, the urine is made 

 use of as a natural clyster for their evacuation. The cloaca is 

 therefore thicker and more rugous than the intestine; and at 

 the moment of laying and of coition, it is everted, (the velabrum 

 which covers it being raised as I have already said,) the lower 

 portion of the bowel being as it were prolapsed. At this mo- 

 ment all the foramina that terminate in the cloaca are conspi- 

 cuous ; on the return or reduction of the prolapsed portion, 

 however, they are concealed, being all collected together as it 

 were into the common purse or pouch. 



The more conspicuous foramina, those, viz. of the anus and 

 uterus, are situated, with reference to one another, differently 

 in birds from what they are in other animals. In these the 

 pudendum, or female genital part, is situated anteriorly between 

 the rectum and bladder ; in birds, however, the excrementitious 

 outlet is placed anteriorly, so that the inlet to the uterus is 

 situated between this and the rump. 



The foramen, into which Fabricius believes the cock to inject 

 his fluid, is discovered between the orifice of the vulva and the 

 rump. I, however, deny any such use to this foramen ; for in 

 young chickens it is scarcely to be seen, and in adults it is pre- 

 sent indifferently both in males and females. It is obvious, 

 therefore, that it is both an extremely small and obscure orifice, 

 and can have no such important function to perform : it will 

 scarcely admit a fine needle or a bristle, and it ends in a blind 

 cavity ; neither have I ever been able to discover any spermatic 

 fluid within it, although Fabricius asserts that this fluid is stored 

 up there even for a w T hole year, and that all the eggs contained 

 in the ovary may be thence fecundated, as it is afterwards 

 stated. 



All birds, serpents, oviparous quadrupeds, and likewise 

 fishes, as may readily be seen in the carp, have kidneys and 



