138 NATURAL HISTORY 



GENUS XIV. 



K E R O N A. 



Animalcules, furnished with hooks (uncini), bristles 

 {selcE), or horn-like processes ; they form part of the 

 section Oxi/trichinay Book III. 



321. Kerona pustulata. The bladder-claw animalcule, 

 — ^This species is large, and is very generally to be found 

 in vegetable infusions. They are difficult to examine, from 

 their irritability under the microscope, rapidly changing 

 their course from one direction to another, thereby fa- 

 tiguing the eye, and confusing the attention of the ob- 

 server. Figure 198 represents a full-grown specimen 

 lying on its back, and producing a current in the water. 

 The mouth- aperture is a longitudinal opening, furnished 

 with cilia, and five hooks or claws on the left side -, the 

 absence of which in the genus Oxytrkha distinguishes it 

 from this. Figure 197 is a side view, shewing the man- 

 ner in which it creeps. Independently of its usual mode 

 of propagation by transverse division, there are two other 

 methods by which the species is increased : one, by a 

 germ issuing from the side of the parent, which, when 

 sufficiently matured, is severed from it ; they are distin- 

 guished from those animalcules produced by division by 



