96 PROFESSOR O. BUTSCHLl. 



even to confusion. It is absolutely peculiar in that the proto- 

 plasm is surrounded by many bands of high refractive index, 

 of somewhat irregular outline. It is clear that it is not 

 dependent on a spirally ribbed sheath. Nothing at all can 

 be made out in the body of the organism beyond this band- 

 ing ; there is no trace of any granular contents, or granular 

 plasma, and no nucleus, with its peculiar arrangements, such 

 as is found in this neighbourhood in Lophomonas hlattarum. 

 Once a clear spot like a vacuole was seen at the anterior end 

 of a specimen. Dying specimens conduct themselves quite 

 peculiarly, for in them the body becomes broken up into a heap 

 of threads, since the banded structures become separated, and 

 lie confusedly on each other. This phenomenon seems to 

 show that the chief part of the body is made up of such 

 threads, as all that was visible between these broken down 

 masses of threads, were small, round, and pale granules. 

 This species when fresh moves as rapidly and energetically by 

 means of its tuft of cilia as the ordinary Z/0^7iomo«a5 hlattarum, 

 but like the latter it dies after a short time in indifferent 

 fluids. They are found more rarely than Lophomonas 

 hlattarum, but sometimes they are found together in the same 

 animal. Leydig appears to have observed a species of this 

 genus in Gryllotalpa, 



Uvella, Ehrenberg {' Die Infusionsthiere als vollkom- 

 mene organismen,' p. 19). 



Uvella virescens (Bory), Ehrenberg (op. cit., p. 20, 

 pi. i, fig. 26). 



Uvella ?;eVe5cew5, Dujardin ('Hist. Nat. des Infusoires,' 

 Paris, 1841, p. 301). 



Uvella virescens, Perty (' Zur kenntniss klemster Lebens- 

 formen,' etc., p. 176, pi. xiv, fig. 1). 



Uvella virescens, Fromentel (' Etudes sur les Microzoaires,' 

 Paris, p. 238, pi. xxvi, fig. 7). 



This commonly occurring form consists of spherical free- 

 swimming colonies, the constituent individuals of which are 

 united in the centre of the colony by their tapering posterior 

 ends (fig. 22, a). They are not, however, connected below, 

 and are not embedded in a common case. Each of the 

 yellowish or yellowish-green individuals on that pole which 

 is furthest away from the centre of the colony has two large 

 flagella which arise close to each other. The number of 

 individuals which unite to form a colony is very variable. 

 Fig. 22, a shows such a colony composed of only a few 

 individuals ; for Ehrenberg has found as many as eighty in a 



