144 METAMOEPHOSES OE MAN 



as suckers, by which the animal adheres to submerged 

 bodies. 



At first the young ascidian swims about very nimbly, 

 but its energy is soon exhausted, and after a few 

 hours it becomes permanently fixed. The prolonga- 

 tions of the yellow mass are drawn toward the centre 

 of the body, the tail becomes atrophied and is detached, 

 here and there may be seen traces of organization, 

 the heart and digestive apparatus gradually appear, 

 and at the end of the third day, all the organs have 

 begun to perform their functions. Simultaneously 

 with these changes the integument is thickened and 

 enlarged. It is this which will form the common matrix 

 for all the inhabitants of the future colony. Numbers 

 of buds now appear upon the body of this solitary 

 animal ; these force their way through the matrix and 

 reach the external surface in a certain definite order, 

 constant for each species, and then, instead of a single 

 isolated ascidian, there is a cluster of compound 

 mollusks, each of which will produce eggs at the 

 proper time. * 



We see then, that in the ascidians, as in the aphides, 

 an animal which has sprung from an egg develops, 

 without previous sexual intercourse, a number of new 

 beings, and finally, coming under the ordinary law, 

 deposits true ova. 



