596 DESCRIPTION or yPolygadrica. 



Urostyla grandis. — Body -white, semi-cylindrical, rounded at the 

 ends ; anteriorly slightly enlarged, hence club-shaped ; styles short, 

 mouth cleft, large, l-4th to l-3rd the length of the body ; it has long 

 cilia on both sides ; the discharging orifice has from five to eight little 

 styles on the left side only; the stomach juice is colourless. The 

 young animalcules are flatter than the old ones. Fig. 342 represents 

 an under view with glands, vesicle, and the cells filled with Bacdlaria 

 and coloured matter. Currents produced by the vibration of the 

 cilia about the mouth are also indicated in the drawing. Found on 

 slimy dead sedge leaves. Size l-144th to l-96th. 



Genus Stylonychia. — The armed Animalcules are ciliated, and 

 armed with styles and uncini. These organs of locomotion are 

 variously disposed. In one species the course of the alimentary 

 canal, with its numerous digestive cells, has been seen ; in the others 

 coloured food is received in the cells ; a thick granular ova cluster 

 exists in all the species ; in two of them two glands ; and in four, 

 contractile vesicles. Transverse and longitudinal self-division occurs 

 in two species; transverse only in a third, and in S.' pustidata, the 

 formation of gemmae is seen. 



S. mytihis {Trichoda mytilus, Kerona mytihis, M.) — Body white, 

 flat, oblong, slightly constricted in the middle, obliquely dilated 

 anteriorly in the form of a mussel. The extremities are so trans- 

 parent that they give it the appearance of being covered with a 

 shield, but they are soft, flexible, and furnished with cilia. The 

 stomach juice is colourless, the middle of the body is sometimes 

 filled with delicate white granules (ova). This animalcule generally 

 has a peculiar thrusting forward and back movement, but can climb, 

 run, and swim nimbly, usually with the back undermost. Dr. 

 Ehreuberg found a single animalcule lived nine days : during the 

 first twenty-four hours it was developed by transverse self-division, 

 into three animals ; these in twenty-four hours more formed two, 

 in the same manner ; so that, by self-divison only (without ova), 

 these animalcules increase three or four-fold in twenty-four hours, 

 and thus a million may be produced from a single animalcule in ten 

 days. An abundant supply of food favours self-division. Found 

 in infusions and amongst Oscillatoria, Size 1-24 0th to l-96th, 



S. pmtulutu (^Trichoda ucarus, M.) — Body white, turbid, ellip- 



