061 DfescRiPTiON OF [^Rotatoria. 



bodies, is itself of greater or less kmgth, but always present. We 

 therefore think that but two genera can be rightly established ; one, 

 Callldina, characterized by the feeble development of its ciliated 

 rotary organ, and by entirely wanting red specks ; the other. Rotifer, 

 with two or several red points placed more or less near the exterior 

 extremity, and, what is of more importance, with very highly de- 

 veloped rotary organs." 



" The genera Ilydrias and Typhlina are fouiided on imperfect ob- 

 servations made by the author during his journey in Eg}^)t ; and the 

 genus MonoJahis ought to be placed elsewhere." 



The family Philodincea thus formed, is arranged parallel with 

 Bracliioncea, as though the absence of a lorica were the only differ- 

 ence between them. 



So far as Dujardin accepts of the same species, his family Rotifer a 

 and that of Philodincea of Ehrcnberg correspond. 



Genus Callidina. The leautiful Rotatorial Animalcule. — Charac- 

 terized by "wanting visual organs, and by possessing a proboscis, and 

 a foot, furnished with processes resembling horns. The vibratile, or 

 rotatory organ, is double, but not pcdicled ; anteriorly is a thickly 

 ciliated proboscis. The furcate foot has two elongated toes, four 

 little horns or processes, and six points. Two muscles for moving 

 the foot are also visible. The oesophageal head has two jaws, with 

 nnmerous delicate teeth. The filiform alimentary canal has a bladder- 

 like expansion posteriorly, but is not provided with glands ; it is 

 siu'rounded by a granular and cellular mass, whose function is un- 

 known ; Ehrenberg thinks it connected with reproduction ; an 

 ovarium, with single large ova, is seen ; a little spur-like process, 

 projecting from the neck, may be a respiratory tube ; no indication 

 of a nervous system is observable. 



C. elegans. — Body spindle-shaped, ciystalline ; rotatory organs, or 

 Avhecls, small. Eigs. 470 to 472 represent this animalcule in different 

 states of extension or contraction. Eig. 473 shows the eggs. Eound 

 in bog water and infusions of oak bark. Length l-72nd. 



C. rediviva (Ehr.) — Body fusiform, diffusely graniJar or else 

 fleshy ; with red, distinct ova, and strong rotaiy organs. Length 

 l-60th to l-48th. Of ova 1-5 76th. Berlin, in the sexliment of 

 water- spouts of houses. 



