692 ORDER PERITRICHA. 



presenting numerous sinuosities ; compound pedicle or zoodendrium not 

 articulate, branching in a subumbellate manner. Length of zooids 1-250". 

 HAB. Fresh or almost stagnant water. 



The figure and diagnosis of this species, as given by Messrs. Claparede and 

 Lachmann,* suffice to prove its distinctness from Carchesium spectabile, with which 

 they originally proposed to identify it. The authors quoted met with it in abundance 

 on the edges of the canal near the Place de I'OpeVa, Berlin, the water of which is 

 usually in a more or less fetid state. The individual animalcules, they report, are 

 nearly twice the size of those of C. polypinum. 



Carchesium epistylidis, C. & L. PL. XXXVI. FIGS. 12-14. 



Bodies elongate-conical, abruptly narrowed near their point of juncture 

 with the pedicle ; the peristome-border slightly dilated, pyriform but not 

 plicate when contracted ; the cuticular surface smooth ; zoodendrium 

 branching subdichotomously, more or less distinctly articulate, such articu- 

 lations usually occurring immediately beneath each bifurcation ; endoplast 

 band-like, curved, transversely disposed. Length of bodies 1-500". 



HAB. Pond and river water. 



This species is described by Claparede and Lachmann as manifesting in its general 

 bearing the more rigid aspect of an Epistylis rather than that of a Carchesium, the 

 independently contractile properties of the separate pedicles determining, however, 

 its true position. The examples furnishing the original description of this type were 

 found attached in small colonies of five or six animalcules only to the bodies and 

 protective cases of the larvae of Phryganidae and other water insects. In the figure and 

 description given by the authors quoted, the former being reproduced at PI. XXXV. 

 Fig. 12, some four or five zooids only are reported as being included in a single 

 colony-stock. During the spring of the year 1879, the author, however, received 

 from Mr. H. E. Forrest, of Birmingham, drawings and specimens of a species 

 agreeing in all essential particulars with the present type, excepting that the colony- 

 stocks usually supported a considerably larger quantity of animalcules varying in 

 number from eight or ten to as many as twenty or thirty while the reported 

 habitat differed to the extent that they were found attached to willow-roots, the 

 polyzoaria of Plumatella repens, and other stationary objects. It was further observed 

 that the surface of the branching pedicle or zoodendrium was usually more or less 

 encrusted with a granular or flocculent deposit. In the original communication 

 received respecting this form, Mr. Forrest indicated its distinctness from Carchesium 

 polypinum in the following points : " (i) In being more sluggish in its movements; 

 (2) in the contours of the animalcules, which are comparatively narrower ; (3) in the 

 presence of brown flocculent matter covering the surface of the pedicle (this possibly 

 accidental) ; (4) in the distinct division of the pedicle at intervals by transverse 

 septa, which usually occurs just below the point of dichotomy." It was at first 

 anticipated by the author that this very distinct form was probably identical with the 

 little known Carchesium spectabile previously described, but a subsequent reference 

 to the original delineation of that type, as given by Rosel, here reproduced, has not 

 supported such identification. A more careful analysis of its leading characteristics 

 has since elicited its entire correspondence, excepting for its more luxuriant form of 

 growth and non-parasitic habitat, with the C. epistylidis of Claparede and Lachmann, 

 and it is therefore here accepted as a local and prolific variety only of that form. As 

 all ecto- and endo-parasitic and commensal species may be held to have originally led 

 an independent existence, it might be reasonably predicated that the present luxuriant 

 and independent growth-form represents the more normal and primitive expression of 



* ' Etudes sur les Infusoires,' 1868. 



