320 DESCRIPTION OF [Polygastrica. 



animalcule in 1820 amongst conferva, but has not lately 

 seen it. It vibrates, runs, and climbs quickly. Figs. 338, 

 339, represent two views of this animalcule. Size 1 -430th. 



Genus CXXVII. KERONA. The claw Animalcules 

 are provided with cilii and uncini, but not with styles. 

 The body is ciliated, besides which, upon the under sur- 

 face, there are claws, and perhaps setae. Numerous digestive 

 cells indicate the polygastric structure; the mouth, and 

 probably the anal spot, are upon the ventral surface. The 

 propagative system is double, consisting of ova glands, 

 and a contractile vesicle. Self-division has not been 

 observed. 



543. KERONA polyporum. The oval polypi Kerona. 

 Body whitish, depressed, elliptical, and reniform ; it has 

 a series of cilii around the frontal region, produced from 

 below the mouth; Ehrenberg counted above forty diges- 

 tive cells, many of them filled with brownish (half-digested 

 green) Monads. Between the cells are ova granules. 

 Fig. 340 is a back view, and 341 a side view, climbing. 

 Parasitic on Hydra vulgaris and polypi. (See Microscopic 

 Cabinet, plate vii.) The latter die when infested with them. 

 Size l-144th. 



Genus CXXVIII. UROSTYLA. The style Animalcules 

 are provided with cilii and styles, but destitute of uncini ; 

 the cilii are thickly disposed in numerous series, those near 

 the mouth being longest. On the ventral surface, at the 

 posterior end, is a small cleft, provided with non-vibratile 

 setae. The numerous digestive cells receive colour and 

 large bodies ; a gland, a contractile sexual vesicle, and 

 delicate granulated ova, represent the propagative system. 

 Transverse self-division also has been observed. 



