108 Dr. R. Greef on the Structicre and 



genus Opercularia with Epistylis^ so that of the eight original 

 genera of Ehrenberg's Vorticellan family three were elimi- 

 nated, namely Stenfor, Urocentrum, and Opercularia. 



On the other hand, however, Clapav^de and Lachmann, 

 following Stein's example, included the Ophrydma (which 

 Ehrenberg had placed, as carapaced hell-animals^ in a separate 

 family) in the Vorticellan family, side by side with tlie true 

 naked Vorticellina, taking into consideration, certainly with 

 justice, the in other respects similar habit and organization of 

 the carapaced and naked forms, and regarded the gelatinous 

 envelope of the Qplirydina as morphologically equivalent to 

 the gelatinous stem of the Vorticelhe^ which is secreted by 

 similar processes, and especially to the rigid stem of Epistylis. 

 From Ehrenberg's Ophrydina^ which included the genera 

 Ophrydium^ Tintinmis^ Vayimcola, and CotJiurnia, before in- 

 corporating them with the Vorticellina, they separated Tin- 

 tinnusj on account of the essential differences in its ciliation 

 and organization ; so that, by this addition of three genera, the 

 original number of the members of the family was reesta- 

 blished. But, besides this, three new genera were added, 

 namely Laye?iophrys in the place of Ttntt'nnus, as a carapaced 

 Vorti'cella, and the two naked forms, Scypliidia and Gerda — 

 the first established by Stein *, the second by Dujardin but 

 first accurately characterized by Lachmann t, and the third 

 discovered by Lachmann and Clapar^deJ. 



With all these additions and deductions, therefore, the 

 Ehrenbergian family of the Vorticellina had grown to eleven 

 genera, with a very considerable number of species. As the 

 characters of this family, those previously established by 

 Ehrenberg, (with the exception of the polygastric nutritive 

 apparatus, which Ehrenberg had assumed for all Infusoria, 

 and therefore, of course, for the bell-animalcules), were essen- 

 tially retained by Clapar^de and Lachmann, especially as re- 

 gards the position of the mouth and anus, whilst at the same 

 time they added the adoral ciliation, which was not indicated 

 by Ehrenberg as a special character, and which they repre- 

 sented, from Lachmann's observations, as running round the 

 ciliary disk in a spiral line and sinking into the buccal 

 orifice. 



In order to trace the fate of the Vorticellan family to its 

 present constitution, it only remains for us to mention briefly 

 the alterations which Stein, in his most recent work on Infu- 

 soria, has finally made in the system gradually elaborated by 



* Die Infusionsthiere auf ihre Entwicklungsg. untersucht, p. 85. 

 1 Miiller's Arcbiv, 1856, p. 348, note 1. 

 I Etudes &c. i. p. 117. 



