686 ORDER PERITRICHA. 



Vorticella elongata, From. 

 PL. XXXV. FIG. 25 (?) and PL. XLIX. FIG. 32. 



Body subcylindrical or elongate-conical, from two to three times as long 

 as broad ; the posterior extremity conically pointed ; the anterior margin 

 slightly expanded ; peristome forming a conspicuously raised border round 

 the somewhat elevated dome-like ciliary disc ; cuticular surface trans- 

 versely striate ; pedicle stout, its relative length unrecorded, contracting 

 spirally or in folds. Length 1-400". HAB. Fresh water. 



An animalcule has been recently obtained by the author from pond water in 

 the neighbourhood of St. Heliers, Jersey, that would appear to correspond with 

 the Vorticella elongata of De Fromentel, but it is of somewhat larger size, varying 

 from 1-300" to 1-250". Its habits are solitary, a few only, scattered at distant 

 intervals, being found on each small fragment of Conferva examined. The pedicle 

 was slender, and four or five times longer than the attenuately-conical and con- 

 spicuously striated body. Its internal muscular cord presented, in all instances, 

 as shown at PI. XXXV. Fig. 25, a finely granulate aspect, closely resembling, 

 except for the absence of colour, that attributed by Ehrenberg to Vorticella picta. 

 De Fromentel figures and describes a second animalcule under the title of Vorti- 

 cella multangula which agrees so closely with V. elongata that the author cannot 

 regard the two as otherwise than identical. This second species is associated by 

 him with the title given in reference to the apparent zigzag course described by the 

 muscular fibrilla within the pedicle, a*id which he reports as having been observed 

 by him in but one other species, his V. margaritata. Such a disposition of the 

 muscular fibre, correctly spiral, is common, however, to all the members of the 

 genus, and is actually delineated by him in the majority of the species he describes, 

 including even the present form. 



Vorticella chlorostigma, Ehr. PL. XLIX. FIG. 33. 



Body conical-campanulate, about twice as long as broad, the frontal 

 margin considerably dilated ; parenchyma green, densely granular ; cuti- 

 cular surface transversely annulate ; pedicle thick, four or five times longer 

 than the body. Length 1-240". HAB. Fresh water ; social. 



This species, excepting for its bright coloration, would appear to agree entirely 

 in shape, size, and cuticular striation with Vorticella convallaria ; it is reported by 

 Ehrenberg as occurring abundantly in the neighbourhood of Berlin, where it is often 

 found covering the stem of grasses and other submerged objects so densely as to 

 present to the unassisted eye the appearance of bright green slime, resembling that 

 formed by the still larger green Trumpet-animalcule, Stentor viridis. The Vorticella 

 fasciculata of O. F. Miiller is referred to by Ehrenberg as being possibly identical 

 with this species. It forms similar dense green masses upon the surface of 

 aquatic plants, but the separate zooids would appear to possess a shorter, broadly 

 campanulate contour, which more closely corresponds with that of V. citrina. 



Vorticella convallaria, Linn. PL. XLIX. FIG. 34. 



Body conical-campanulate, about twice as long as broad, the frontal 

 region dilated, slightly revolute ; parenchyma whitish or hyaline ; cuticular 

 surface transversely annulate ; pedicle rather thick, from three to six times 

 the length of the body. HAB. Stagnant water and infusions ; social. 



As previously mentioned, this species represents one of the first discovered 

 infusorial forms, it being identical with the so-called "animalcules of the first size" 



