GENUS URONYCHIA. 



797 



Genus IV. URONYCHIA, Stein. 



Body oval, encuirassed, turgid, the sides rounded, truncate in front, 

 with a prominent membranous upper lip ; the hinder extremity havino- 

 developed on the ventral surface two converging bow-shaped fissures, into 

 which the short, claw-shaped, anal and marginal uncini or styles are 

 inserted ; ordinary ventral and frontal styles entirely absent ; the peristomal 

 excavation pocket-shaped, closing sphincter-wise at will, its inner or right- 

 hand border bearing a band-shaped undulating membrane. 



The type and as yet single known species of this genus is the TricJwda imnsfuga 

 of Miiller and Plxsconia scutum of Dujardin and Stein's earlier writings. The present 

 generic title was conferred upon it by Stein * in the year 1865. 



Uronychia transfuga, Miill. sp. Pl. XLV. Figs. 34-36. 



Body ovate, truncate in front, slightly narrower posteriorly, more usually 

 obliquely truncate, angular, and bent towards the left, but sometimes evenly 

 rounded, the lateral margins symmetrical ; peristome-fossa extending from 

 the anterior end to the centre of the body, widened posteriorly ; the surface 

 of the dorsal region sometimes smooth, sometimes longitudinally ribbed ; 

 anal uncini and styles variable in character and number, usually from three 

 to seven or eight recurved and occasionally fimbriate uncini inserted in the 

 right-hand posterior cleft, but not more than two on the opposite one ; 

 each of these fascicles occasionally supplemented by two fine simple setse. 

 Length of body 1-288". Hab. — Salt water. 



This species appears to be subject to a wide range of both local and individual 

 variation with respect to the number and character of the stylate appendages 

 of the posterior extremity of the body. In some instances these appendages are 

 straight, or but slightly bent, in others strongly curved or uncinate, while in 

 a third series they are branched in an elegant feather-like manner. The posterior 

 termination of the carapace, and also the character of its dorsal surface, as shown 

 in the diagnosis, exhibits a similar tendency to vary. There can be but little 

 doubt, the above facts considered, that the Campylopus paradoxus of Clapar^de 

 and Lachmann j is, as anticipated by Stein, identical with this species, though these 

 last-named authorities seem to have failed in detecting the undulating membrane 

 on the right border of the peristome, and which without very careful examination 

 is likely to escape notice. The author has obtained this singular animalcule from 

 Brighton and the Jersey coast, and also in sea-water from the Aston Aquarium, 

 Birmingham, remitted by Mr. Thos. Bolton. 



Genus V. EUPLOTES, Ehrenberg. 



Animalcules free-swimming, encuirassed, shield-shaped, elliptical, or 

 orbicular, with sharp laminate marginal edges, and usually a plane ventral, 

 and convex, sometimes furrowed, dorsal surface ; peristome-field arcuate, 

 extending backwards from the frontal border to or beyond the centre of 

 the ventral surface, sometimes with a reflected and ciliate inner border ; 

 frontal styles or uncini six or seven in number ; three or more irregularly 



* •'Bohmische Gesellschaft der Wiss.,' Bd. x. 



t 'Etudes sur les Infusoires,' 1858. 



