REPRODUCTION 3 



conditions which now exist hfe never starts anew, but is always 

 passed on from one Hving being to another which arises from it. 

 A living being which divides to produce others is a parent ; 

 those which it forms are offspring. These are always at first unlike 

 the parent. There are certain creatures, like Amoeba, mentioned 

 above, in v^hich the only evident difference between the offspring 

 and the individual by whose division they arose is the necessary 



Fig. I. — Human ovum from the uterus. X 480. — From Hamilton, Boyd and 

 Mossman, Human Embryology, 1945. Heffer and Sons, Cambridge. 



one of size, but in the great majority of cases there is also an obvious 

 difference in form, the offspring being at first very unlike the parent 

 in structure. This difference is obscured in the case of man and 

 some other animals, where the offspring (Fig. i) undergoes 

 changes in the womb before birth, but it is seen unmistakably in 

 animals which are born in the condition of an egg. In their 

 immature condition the offspring are known as reproductive 



bodies. 



In spite of this unlikeness at starting, the oftspring become in 

 time Hke the parent or parents from which they arose, though 



