788 ORDER HYPOTRICHA. 



border ; marginal setae set within the periphery, and excurrent only at the 

 posterior extremity ; a supplemental border of very short, hair-like, or hispid 

 setae projecting at right angles down each lateral margin ; endoplasts two in 

 number, ovate ; contractile vesicle situated close to the left-hand border 

 a little in advance of the median line. Length 1-200" to 1-150". 



HAB. Fresh water ; parenchyma usually enclosing rust-coloured 

 granules. 



This and the two following species are described by Wrzesniowski in his account 

 of the Infusoria of Warsaw.* 



Oxytricha macrostyla, Wrz. 



Body flexible, but not contractile, elongate-lanceolate, about five times 

 as long as broad, the anterior extremity rounded, gradually tapering from 

 the centre, narrowest and somewhat pointed posteriorly ; peristome-field 

 extending backwards to a distance of about one-quarter of the length of the 

 entire body, furnished with a double, lip-like process ; possessing seven or 

 eight uncinate frontal styles, five ventral styles, disposed quincuncially as 

 in O. (zruginosa, and five large, stout, incurved anal styles, which do not 

 project beyond the posterior extremity; marginal setae forming an even, 

 projecting lateral border, increasing in length and prominence towards the 

 posterior extremity ; a supplemental border of fine hispid setae developed 

 down the right and left peripheral margins ; contractile vesicle situated 

 close to the left-hand margin, in front of the median line ; endoplasts two 

 in number, ovate. Length 1-200". HAB. Fresh water. 



Oxytricha sordida, Wrz. 



Body lanceolate, about three and a half times as long as broad, the 

 right-hand border convex, the left one indented, the anterior extremity 

 narrower and curved slightly towards the left ; bearing three anterior uncinate 

 and three more posterior setose frontal styles ; five scattered ventral setae, 

 and four or five slender, projecting anal styles ; marginal setae forming a 

 continuous peripheral border, longest towards the posterior extremity ; 

 contractile vesicle situated close to the centre of the left lateral border. 

 Length 1-200". HAB. Fresh water. 



Oxytricha scutellum, Cohn. PL. XLIV. FIGS. 17 AND, 18. 



Body highly retractile, oblong, flattened, rounded posteriorly, pointed 

 anteriorly, about twice as long as broad when extended, nearly orbicular 

 when contracted ; peristome-field extending backwards to a distance of 

 one-third of the length of the expanded body ; a transverse row of about 

 twelve slender anal styles projecting at the posterior extremity ; contractile 

 vesicle single, central ; parenchyma grey, more or less granular. Length 

 1-480" to 1-360". HAB. Salt water. 



Cohn omits, in his figures and description of this species, to record the character 

 * 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xx., 1870. 



