B. VII. 1 THE HISTOKY OF AKIMALS. 189 



mother, and the different parts of the body resemble either 

 parents. Twins have sometimes no resemblance to each other, 

 but they are generally much alike ; and one woman coha- 

 bited with a man, and conceived seven days after parturi- 

 tion, when she bore a child as like her former as if they had 

 been twins. Some women, as well as other creatures, pro- 

 duce young resembling themselves, others bear those which 

 resemble the male, as the horse called Dicsea in Pharsalia. 



CHAPTER VII. 



1. THE seminal fluid in its emission is preceded by wind. 

 The manner of its emission exhibits this; for nothing is 

 expelled to a great distance without pneumatic force. If the 

 seminal fluid is taken up by the uterus and retained there, 

 it becomes inclosed in a membrane. For if it is expelled 

 before it becomes articulated, it appears like an ovum inclosed 

 in a membrane, but without any shell, and the membrane is 

 full of veins. All animals, whether furnished with fins, feet, 

 or wings, whether viviparous or oviparous, are produced in 

 the same manner, except that the umbilicus in viviparous 

 animals is turned towards the uterus, and in others to the 

 ovum ; and in some cases both ways, as in a certain kind offish. 

 Some of them are surrounded by a membrane, others by a 

 chorion. First of all, the foetus is contained within the last 

 envelope. Then there is another membrane over this, which 

 is in part united to the matrix and is partly separate, and 

 contains water. Between these is a watery or sanguineous 

 fluid, which in women is called prophorus. 



2. All animals that have a navel increase by the navel '> 

 and in those which have acetabula the navel is united to the 

 acetabulum ; and in those which have a smooth uterus the 

 navel is united to the uterus upon a vein. The position of all 

 quadrupeds in the uterus is stretched out ; that of fishes is on 

 the side ; bipeds, as birds, are folded together. The human 

 foetus lies folded up with its nose between its knees and its 

 eyes upon them, and its ears turned outwards. All animals are 

 alike in having the head placed upwards at first. As they 

 grow, the head turns round, and the birth of all animals is 

 naturally with the head forwards ; for even in those that are 

 folded together the presentation of the feet is unnatural. 

 The embryo of quadrupeds contains excrementitious matter, 



