THE BEGINNINGS OF LIFE. 485 



isms J < (Fig. 89, g) which increase in size, and subse- 

 quently make their way through the integument of the 

 Rotifer in which they have been formed. They take 

 all varieties of food lying in their way, after the manner 

 of an Amoeba, and thus increase considerably in size. 

 They then assume a spheroidal shape and protrude 

 pseudopodia, so as to become converted into Actino- 

 phrys, which, after still further increasing in size, retract 

 their rays, undergo an internal elaboration, and then 

 develop cilia on different parts of their surface. They 

 thus become converted into specimens of the higher 

 Ciliated Infusoria belonging to the families Keronae or 

 Oxytrichse. And, similarly, specimens of Actinophrys 

 which have originated more directly from the Rotifer 

 may also, according to Dr. Gros, pass through such trans- 

 formations. Other specimens, however, attain a very 

 large size, and are often seen to detach portions of 

 their substance which have the power of developing 

 into one or other of the forms of Ciliated Infusoria, 

 although the larger parent-masses may undergo different 

 transformations 2 . 



But other Rotifers, instead of giving birth to speci- 

 mens of Actinophrys and Peranema, or to either of 

 these forms alone, may become resolved into a number 



1 And, according to Dr. Gros (loc. cit, p. 435), they may arise in 

 many different modes. See pp. 459 and 549. 



a Dr. Gros says: '-S'il n'est pas toujours possible de dire, a premiere 

 vue, ce que doit devenir tel Actinophrys, puisque la transformation finale 

 tient k la taille, a la ddrivance, a 1'abondance de nourriture, etc., un trait 

 qui est gnral, c'est qu'ils tendent tous vers les utriculeux cilies.' (p. 436.) 



