VarticeWmi.l iNFtTscRTA.L .vNiMALCunRS. 521 



man, Mr. Bi'ightwcll, of Norwich. Their several researches arc 

 given, M'ith the special account of the genus to which they relate. 



Of the several genera named and distinguished by Ehrenberg, two 

 only are accepted by Dujardin, viz., Epktylis with a rigid pedicle, aul 

 VorticeUa Avith a contractile stalk, simple or bi'anched. " He would 

 comprehend the genus Carchesium with the latter," for a generic 

 character is not to be found in the simple or branched condition of 

 the stalk, the bodies being similar. " As to the genera Opercular ut, 

 .and Zoothamiiium, we have not met with them, having the character 

 assigned by Ehrenberg." A third genus, under the name of Scj/phi- 

 dium, is established by us for the sessile species ; whilst a fourth, 

 Vaginicola, comprises all those species invested with a membranous 

 sheath. Dr. Stein, in his researches on the development of Vagi- 

 nicola, shows that the presence or absence of a pedicle is accidental, 

 depending upon the stage of development, and that it cannot bo 

 employed as a generic distinction. This being the ease, Scyphidiuni 

 must merge Avith Vaginicola. 



The genera Stentor, TrichocUm and Vrocentrum enter into the for- 

 mation of the familj" Urceolariens, of Dujardin ; and, on tho other 

 hand, the Vaginicola of this naturalist are placed by Ehrenberg in 

 the family Ophrydina. 



The Vortieella live for the most parts in sweet water, fresh, or 

 marine, in which they are met with, attached to plants or shells to 

 some Crustacea, or to larvae of insects. There are, however, Vor- 

 ticellce and Scyphidece produced in infusions, and even in fetid ones. 



Genus Stentoe. — TJie trumpet Animalcules comprehend cilated tail- 

 less Vorticellina which have no pedicle or stalk, but are free, or 

 attached by the posterior extremity of their bodies. The body is 

 conical, but admits of very considerable modifications of form, and 

 is entirely covered with cilia : a wreath of larger ones surmounts 

 the forepart. The function of locomotion is performed by the cilia j 

 the anterior wreath likewise constitutes a special organ for purvey- 

 ance. Ehrenberg considers the longitudinal stria) along the body, 

 and the circular ones at the anterior part, muscular fibres. The 

 anterior wreath of cilia is coiled in a spiral form, about the mouth ; 

 and in some species a row of long ones proceed from the mouth, in 

 a fringe-like manner, to the middle of the body, The nutritive 



