770 ORDER HYPOTRICHA. 



a row of fine marginal setae developed along each lateral border; two 

 median rows of similarly fine ventral setae; an even transverse row of 

 eight or more slender anal styles projecting beyond the posterior extremity ; 

 contractile vesicle situated in the posterior third of the body ; colour of 

 parenchyma yellow or light brown. Length 1-130" to 1-120". 

 HAB. Salt water. 



This animalcule is recorded by Cohn * as a species of Oxytricha. The same 

 authority further describes as a variety of this type, under the title of Oxytricha flav a 

 var. carnea, a flesh-coloured species having twice the breadth and thickness of the 

 typical form, and which is abruptly truncate and not narrower at the posterior 

 extremity. The variety in question is further distinguished by the possession of four 

 longitudinal rows of bright red corpuscles which ornament the parenchyma, as 

 seen from the ventral surface. 



Holosticha rubra, Ehr. sp. PL. XLIII. FIG. 17. 



Body highly flexible and retractile, elongate-lanceolate, almost four 

 times as long as broad, slightly tapering towards and equally rounded at 

 each extremity ; the peristome-field extending backwards to a distance of 

 one-third of the length of the entire body ; a transverse row of eight or 

 nine slender projecting anal styles developed at the posterior extremity ; 

 parenchyma brick-red, enclosing two central and two marginal longitudinal 

 rows of minute bright red corpuscles ; contractile vesicle located centrally 

 at a distance of one-fourth of the body-length from the posterior extremity. 

 Length 1-140". HAB. Salt water. 



This species, imperfectly figured and described by Ehrenberg and Dujardin 

 under the title of Oxytricha rubra, was formerly adjudged by Stein and Claparede 

 and Lachmann to be correctly referable to the genus Uroleptus. The presence 

 of a well-developed series of anal styles, as recently demonstrated by Cohn, however, 

 re-establishes its position among the typical Oxytricha, or rather with that offshoot 

 from the genus with which it is here associated. The author has obtained this 

 brilliantly coloured marine species from a variety of sources, including salt water 

 remitted from the Aston Aquarium, Birmingham, by Mr. Thomas Bolton, as also 

 from among decaying zoophytes collected at St. Heliers, Jersey, and Bangor, 

 N. Wales. Ehrenberg, its first discoverer, has recorded the occasional occurrence 

 of the species in such abundance in the North Sea as to communicate a red hue to 

 the water. 



Holosticha oculata, Mereschk. sp. PL. XLIV. FIG. 21. 



Body somewhat variable in form, usually subovate or pyriform, 

 gibbous and inflated in lateral view, about three times as long as broad ; 

 peristome-field arcuate, extending through one-third of the length of the 

 body ; frontal styles uncinate, subequal, four in number ; ventral setae very 

 fine, forming two closely approximated median rows ; marginal setae slightly 

 larger than the preceding, those on the right side projecting entirely, and 

 those on left side only partially, beyond the lateral margin ; anal setae five or 

 six in number, continuous with the left-hand marginal series, projecting 

 beyond the posterior extremity ; endoplast and contractile vesicle not 



* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xvi., 1860. 



