GENERATION OF ANIMALS, IV. iv. 



into the uterus,t " with the result that the parts 

 grow on to one another and get thrown into disorder. 

 [In the case of birds, since copulation is a quick 

 business with them always, the eggs and their colour 

 as well, he says, get thrown into disorder.]^ But if 

 it is a fact that several offspring are formed from one 

 semen and from one act of copulation, as is evidently 

 the case, we should do better not to neglect the 

 shortest route and go a long way round, since in cases 

 of this sort it is absolutely necessary that this should 

 happen when the semens have not been separated 

 but proceed together.*^ Now if we are really obliged 

 to refer the cause to the semen that comes from the 

 male, then, I suppose these are the hnes on which we 

 should make our explanation ; but from every point 

 of view we ought preferably to hold that the seat of 

 the cause is the material ** and in the fetations as 

 they take shape. And that too explains why mon- 

 strosities of this sort, while they occur very seldom 

 in animals that produce one offspring only, occur 

 oftener in those that are prolific, and most of all 

 in birds, and specially in the common fowl.* This 

 species is prolific, not only in laying eggs frequently, 

 as the pigeon tribe does, but also in carrving manv 

 fetations at once and in copulating at everj- season 

 of the year. Hence also fowls lay many twin-eggs, 



* Tfiis sentence (which may be a note on 770 a 15 ff.) seems 

 to be from the same author as the interpolation at 717 b 29 : 

 the speed of birds' copulation obviously was a favourite point 

 with him, but it has nothing to do either with this passage 

 or with that in Bk. I. In the present passage, birds are 

 introduced later by Aristotle (a 10). 



' And this is a contingency for which Democritus's ex- 

 planation does not allow. ■* Supplied by the female. 



* For monstrosities, see references, p. xi. 



4.21 



