THE INFUSORIA. 329 



CLASS II. ROTATORIA. 



Those infusorial animalcules which are included under 

 the great division Rotatoria are distinguished by their 

 being destitute of a true nervous system and of vascular 

 pulsation ; by their possessing a simple tubular alimentary 

 canal, a definite form of body (that is, not alterable by the 

 formation of gemmae, or spontaneous division, as in the 

 Polygastrica), being androgynous, or hermaphrodite, pro- 

 vided with rotatory organs, and, though destitute of true 

 articulated feet, often have a single false foot, or pediform 

 process. 



The magnifying power most useful for the examination 

 of the Rotatoria is 250 ; and with a power of 400 times, all 

 that has been discovered in their internal organization 

 (except in one or two cases) may be seen. 



The following table represents the analysis of the class 

 Rotatoria into families: 



f" margin of cilii-wreath r illoricated Icthydina. 



entire. 



With a simple Holotrocha. Uoricated Oecistina. 



continuous wreath I 

 of cilii. \ 



(MoNOTRocHA.) margin of cilii-wreath rilloricated Megalotrochaea. 



lobed or notched. -I 

 Schizotrocha. Uoricated Floscularia. 



with the cilil-wreath rilloricated Hydatinea. 



divided into several series. < 



With a compound I Polytrocha. Uoricated Euchlanidota. 



or divided wreath / 

 of cilii. \ 



(SoROTHOCHA.) with the cilii-wreath rilloricated Philodinaea. 



I divided into two series. 1 



\- Zygotrocha. Uoricated Brachionaea. 



