OF THE TRACHELINA. 



621 



to the Bursarke, he inchides among them several species in whieh the 

 existence of a mouth is, to say the least, doubtful." 



The genus Bursaria is taken as the representative of a distinct family, both 

 by Dujardin and by Perty. The former, who names it " Bursaiina," insti- 

 tutes five genera, viz. Plagiotoma, Ophryoglena, Bursaria, Spirostomum, and 

 Condylostoma. The latter adopts the same name, and ranges the family in 

 his section Monima, comprehending Ciliata which, although very contrac- 

 tile, and clothed by a soft integument, always retain their form. The genera 

 included among the Bursarina by Perty are Lembadion and Bursaria, — ^the 

 former a new genus established by himself to receive two species which he 

 does not find indicated by Ehrenberg. Dujardin defines the Bursarina as 

 " animals possessing a highly contractile body, very variable in fonn, mostly 

 oval, ovoid, or oblong ; ciliated throughout, and having a large mouth sur- 

 mounted by a band or surrounded by a spirally curved row of cilia." 



The genus Bursaria is closely allied to Paramecium, from which it is 

 chiefly distinguished by the row of larger, longer cilia about the mouth, ex- 

 tending along the deep fossa in which that orifice is contained. In Para- 

 mecium the cilia are everywhere of the same size. 



Several of the Bursarice enumerated by Ehrenberg have been shown to be 

 Opalines, and to be destitute of a mouth. These species are B. Ranarum, 

 B. Entozoon, B. intestincdis, and B. Nucleus, all which are further remarkable 

 in being parasitic in Batrachia. The B. cordiformis is also a parasite of the 

 intestine of the frog, and, although a doubtful member of the genus, has the 

 sanction of Stein to the generic position accorded it. 



a. Sub-genus Buesaria. 



Burs ahi A truncatella (M. ) . The trun- 

 cated Bursaria. — Large, visible to the 

 naked eye ; white, ovate, tm'gid, trun- 

 cated and broadly excavated in front, 

 where there is a simple row of cilia. In 

 some specimens, Ehrenberg saw half-di- 

 gested Rotifera and large quantities of 

 vegetable matter in the nutritive cells, 

 and was able, as he thought, by means of 

 carmine given as food, to trace an ali- 

 mentary canal through the greater part 

 of its com-se. In each vacuole the food 

 appears surrounded by a clear fluid, which 

 Ehrenberg calls bile. A large bright 

 vesicle is seen below the mouth and 

 somewhat to the left of it, on which side 

 is also a large curved but not articulated 

 nucleus, reaching to the brow or frontal 

 region. In ditches and ponds, amongst 

 rotten beech-leaves. 1-48" to 1-36". 



B. Vorticella (xxiv. 294). —White .; 

 large, nearly spherical, and turgid ; an- 

 teriorly tnmcated and widely excavated, 

 with a double row of cilia. Found with 

 Chlamydomo7uis Pulvisculus and Gonium 

 pectorals, which are sometimes seen 

 within it, as in xxiv. 294. 1-108". 



B. vorax. — Large, oblong, rounded at 

 the ends ; mouth ample, being one -third 

 the length of the body, and touching the 

 summit of the frontaf region. This spe- 



The inferior (not anterior) Up reaching to the 

 frontal margin. 



cies has great resemblance to Urostyla 

 grandis and Stylonychia lanceolata, when 

 their claws and styles are withdrawn. 

 In muddy water in summer. 1-140" to 

 1-108". 



B. (Opalina) Entozoon. — Large, cylin- 

 drical, tiu-gid, nearly equally rounded at 

 both extremities; mouth small, near the 

 frontal apex. Found, with the following, 

 in the rectum of Rana temporaria (the 

 Frog), in summer and winter. 



Perty represents this as a mere variety 

 of B. Ranarum. He also treats B. Nucleus 

 and probably B. itdestinaUs as other va- 

 rieties of the same being, and therefore 

 Opalines. 



B. ( Opalina ?) intestinalis ( Vibrio Ver- 

 miculus, M.). — Slender, cylindrical, at- 

 tenuated posteriorly ; mouth small, situ- 

 ated below the frontal apex. In this 

 species, as well as in others, Ehrenberg 

 has seen transverse self-di\-ision. Found 

 with the preceding. 1-240" to 1-120". 

 It is probably an Opalina. 



B. (?) cordiformis. — Reniform, front 

 depressed, mouth slightly curved in a 

 spn-al manner ; colom' white. 1-210". 



This species Stein afiirms to be a trut? 

 Bursaria ; but Perty makes it an Opa- 

 lina, — a view countenanced by its para- 

 sitic nature. 



