GENERATION OF ANIMALS, I. i. 



parts ; and the corporeal " elements," ° as they are 

 called, are the matter for the uniform parts). Con- 

 sequently, of the parts it remains to describe those 

 which subserve animals for the purpose of genera- 

 tion, about which I have so far said nothing definite, 

 and of Causes we still have the Motive Cause to 

 deal with, and to explain what it is. And, in a way, 

 consideration of this Cause and consideration of the 

 generation of each animal comes to the same thing : 

 and that is why our treatise has brought the two 

 together, by placing these parts at the end of our 

 account of the parts, ** and by putting the begin- 

 ning of the account of generation immediately after 

 them. 



Now of course some animals are formed as a result Distinction 

 of the copulation of male and female, namely, animals uni\^ereaL°*^ 

 belonging to those groups in which there exist both 

 male and female, for we must remember that not 

 all groups have both male and female. x\mong the 

 blooded "^ animals, with a few exceptions,'' the indi- 

 vidual when completely formed is either male or 

 female ; but among the bloodless animals , while some 

 groups have both male and female and hence gener- 

 ate offspring which are identical in kind with their 

 parents, there are other groups which, although they 

 generate, do not generate offspring identical with their 

 parents. Such are the creatures which come into 

 being not as the result of the copulation of living 

 animals, but out of putrescent soil and out of resi- 

 dues.* ' Speaking generally, however, we may say 

 that (a) in the case of all those animals which have 

 the power of locomotion, whether they are adapted 



* The passage 715 b 25-30 should be inserted here, if 

 anywhere. 



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