48 THOUGHTS ON ANIMALCULES. 



Vorticellae roam free for awhile, and at length throw 

 out a fresh pedicle, become fixed, and ultimately pro- 

 duce another colony of individuals by spontaneous fis- 

 suration. 



III. The Arborescent VoRTiCELLA, ((7«rcAe5mm, pi. 

 Ill, fig. 1). — In some kinds of Vorticellina the pedicle, in- 

 stead of being single down to its attachment, springs from 

 a common trunk, the individual bodies hans^ino^ at the 

 extremities of the branches like the flowers of the hare- 

 bell : this results from imperfect self-division. In tliis 

 species, the group commences by a single VorticeUa 

 dividing longitudinally into two portions, and thus pro- 

 ducing two perfect individuals, which are connected by 

 a forked stem: these two divide into four, which, in 

 like manner, are united by their pedicles ; and so the 

 process goes on, till the limits of this special type of 

 development are reached. In pi. iii, fig. 2, is shewn 

 the manner in which the longitudinal fissuration takes 

 place. Two distinct cups or bodies are formed, and are 

 seen in progress of separation : each is provided with a 

 distinct set of cilia and digestive organs, as denoted 

 by the coloured spots in each bell : in a short time the 

 division would be completed, and each animalcule sup- 

 ported on a pedicle. The body of this animalcule, 

 when arrived at maturity, separates from the parent 



