42 



CLASSIFICATION OF THE ANIMAL KINGDOM. 



CLASS III. ROTIFERA (ROTATORIA, Wheel-animalcules). 



ORDER I. HOLOTROCHA. (Ecistes, Conochilus. 

 ORDER II. SCHIZOTKOCHA. 



Fam. a. Megalotrocliidse. Megalotrocha. 



Fam. b. Flosculariidse. Floscu- 



laria, Melicerta, Stephanoceros. 

 Fam. c. Hydatinidse. Hydatina, 

 Eosphora (fig. 3*7), Notommata, 

 Polyarthra, Euchlanis. 



ORDER III. ZYGOTROCHA. 



Fam. a. Philodinidse. PMlodina, 



Rotifer. 

 Fam. b. Brachionidte. Brachionus. 



OIIDER IV. GASTEODELA. 



Fam. a. Asplanclinida?. As- 

 planchna. 



ORDER V. PARASITICA. 



Fam. a. Albertiidse. Albertia, 

 JBalatro. 



ORDER VI. GASTROTKICHA. 



Fam. a. Chsetonotidae. Ichtky- 

 dium, Chcetonotus. 



The ChcetonotidcK, or Hairy-backed Ani- 

 malcules, constitute an aberrant group of 

 Rotifers, and are often placed among the 

 Tiirbellaria, or regarded as belonging to the 

 Oligochsetous Annelicles. 

 The genera Albertia, Seison, and Balatro comprise certain abnormal 

 Rotifers, in which there is no wheel-organ, and the cilia are either greatly 

 reduced or wholly wanting. They are ecto- or endo-parasites. 



The genus Pedalion comprises Rotifers with limb-like appendages, 

 moved by special muscles, and it is sometimes regarded as the type of a 

 special section of the Rotifers (Arthroptera). 



The genus Echinoderes, lastly, includes certain minute marine organ- 

 isms, in which the body is imperfectly segmented, but there are no limbs. 

 The anterior segment of the body is furnished with booklets, and consti- 

 tutes a protrusible proboscis. The genus forms a link between the Scol- 

 ecids and the higher Anmilosa. 



Fig. 37. Rotifera. Eosphora 

 aurita, enlarged 250 diameters. 

 (\fter Gosse.) 



