PROCESS OF GROWTH. 163 



tures, and never failed to display their charms to 

 admiring visitors, who rewarded them by unmeasured 

 praise. Twice I had an opportunity of observing 

 an action 1 cannot explain, except by supposing 

 either that the tentacles of the Plumatella have 

 some poison-threads like the polyps, or that rotifers 

 are susceptible of fear. On these occasions the 

 common rotifer was the subject of the experiment. 

 First one, and then another got among the tentacles, 

 and on escaping seemed very poorly. One fellow^ 

 was, to borrow a phrase from Professor Thomas 

 Sayers, ''completely doubled up," and two or three 

 seconds — long periods in a rotifer's life — elapsed 

 before he came to himself again. 



By keeping a colony of the Plumatella for a few 

 weeks in a glass trough, and occasionally supplying 

 them with fresh water from an aquarium, containing 

 animalcules, they are easily preserved in good health, 

 and as tliey develop fresh cells, the process of 

 growth may be readily watched. This production of 

 fresh individuals enlarges the parent colony, but could 

 not be the means of founding a new one, which is 

 accomplished by two other modes. A little way 

 down the cells Professor Allman discovered an ovary 

 attached to the internal tube by a short peduncle^ 

 or foot-stalk, while a testis or male generative 

 organ is attached to the funiculus^ or "little 

 rope," we have already described. 



