688 ORDER PERITRICHA. 



basal extremity. It might be predicted that the compound stock-form Canhesiu?n 

 has been developed from a simple Vorticellidan that exhibited a similar structural 

 peculiarity. 



** Bodies broadly canipamdate. 



Vorticella microscopica, From. Pl. XLIX. Fig. 37. 

 Body conical-campanulate, its surface striate ; peristome-border everted, 

 constricted beneath, its diameter equalling the length of the body, vestibular 

 seta moderately developed ; pedicle slender, contracting spirally, five or six 

 times longer than the body. Length 1-2000". Hab. — Fresh water. 



According to the description and figure given by De Fromentel,* this species 

 closely resembles in shape his V. fascia/Iata, though the stem is shorter and thicker 

 in proportion, and the surface of the body is described as striate, though it is not so 

 figured in the accompanying illustration. The same writer hazards the opinion that 

 the species is possibly identical with the Vorticella pida of Ehrenberg, though upon 

 what grounds such an identity is premised it is difficult to conjecture. 



Vorticella appuncta, From. Pl. XLIX. Fig. 38. 



Body broadly campanulate, widely everted anteriorly, nearly as wide 

 as long; the ciliary disc elevated obliquely in a tongue-shaped form 

 above the margin of the peristome ; cuticular surface finely striate trans- 

 versely ; pedicle rather thick, its relative length unrecorded, enclosing 

 numerous brilliant green corpuscles. Body when contracted globular, 

 invaginate around or overlapping the insertion of the pedicle. Length 

 1-420". Hab. — Fresh water. 



The granular composition of the internal structure of the pedicle of this species 

 finds its analogue in the Vorticella picta of Ehrenberg and in the apparent variety of 

 V. elongata figured by the author at Pl. XXXV. Fig. 25. 



Vorticella monilata, Tatem. 

 Pl. XXXV. Fig. 27, and Pl. XLIX. Fig. 39. 



Bodybroadly campanulate, widest and everted anteriorly ; the peristome- 

 border thick, often revolute, its diameter when fully expanded equalling or 

 exceeding the length of the body ; subspheroidal when contracted ; pharyn- 

 geal cleft deeply prolonged ; parenchyma transparent, colourless ; the 

 entire cuticular surface ornamented with hemispherical bead-like elevations, 

 which are disposed in closely set annular series, those on the peristome- 

 border of the largest size ; pedicle stout, four or five times longer than the 

 body ; endoplast comparatively short, band-like. Length 1-400" to 1-350". 



Hab. — Fresh water ; forming small social colonies. 



This species was first discovered by Mr. J. G. Tatem, who figured and described 

 it under the above name in the ' Monthly Microscopical Journal ' for April 1870 as 

 a probable malformed or monstrous variety of Vorticella coiivallaria. Subsequently, 

 1876, De Fromentel has most imperfectly figured and described it in his ' Microzoaires,* 

 in connection with the newly proposed title of Vorticella margaritata. By neither of 

 these two writers, however, can full justice be said to have been done to the contour 



* ' Etudes sur les Microzoaires,' '876. 



