MICROSCOPIC WONDERS 27 



difficult to say. The life history is of interest on account 

 of the fact that the members of the Suctoria start life as 

 free swimmers, resembling the Ciliata. 



Gradually the young mature, until eventually they become 

 similar fixed objects to their parents. Hence we may say 

 the Acinetaria were probably evolved from the Ciliata some 

 far bygone day. 



A little animal, fastened to a stem or leaf, resembling a 

 model post-horn, swinging gently from side to side, will 

 often be found, when searching for microscopic pond creatures. 

 Or a green, pear-shaped animal may swim with a peculiar roll 

 across the slide, turning over and over until it passes out of 

 the field of view. Perchance two such creatures, fastened one 

 above the other, may make an appearance. 



Stentors, like most other micro-pond animals, multiply, and 

 so should one be found it is more than likely that others will 

 shortly be discovered. 



Stentor Polymorphus is a green little creature, and although 

 able to swim often settles on a favourable spot and produces a 

 temporary foot. 



Thus a colony is founded, which increases until a large 

 number of individuals are closely packed on the same weed. 

 Occasionally a member of the colony will liberate itself and 

 swim by means of the cilia with which its body is covered to 

 a fresh spot, and there start a new colony. From the writer's 

 personal experience it would seem that Stentor Polymorphus 

 is free swimming during certain seasons, and usually sedentary 

 during others. 



The animal itself will be easily recognised by the illus- 

 trations. Illustration No. 1(6) shows Stentor Polymorphus 

 multiplying by division, but it is interesting to know that 

 sexual reproduction also takes place, in which case two stentors 

 join together. Strangely enough, whilst in the act of dividing, 

 the stentor swims actively, changing its shape, contracting and 

 expanding, as if perfecting normal. 



The trumpet shape of the individual, the peculiar twist of 

 the opening of the funnel, and the size of the creature does 

 not allow any confusion in its identity ; for it in no way 

 resembles vorticella, nor can it be mistaken for a rotifer. 



Free-swimming stentors, especially whilst engaged in division, 

 are most interesting to watch, whilst a group of settled 

 stentors, viewed with a dark background, is certainly a beauti- 

 ful picture. 



Stentor Niger or the Black Stentor is a free swimmer. It 

 is a smaller creature than Polymorphus, and not so well dis- 



