7o8 ORDER PERITRICHA. 



branched, striate longitudinally, articulate at one or two intervals between 

 each bifurcation. Length of bodies 1-325". Hab. — Freshwater. 



In shape the animalcules of this species appear to closely resemble those of 

 Epistylis plicatilis, and it is a question whether the chief point of difference cited 

 by De Fromentel, that of the articulation at distant intervals of the pedicle, is 

 sufficient to distinguish them ; more especially as, in the last-named form, Stem has 

 remarked that old specimens are similarly jointed. No mention is made as to the 

 form assumed by the zooids when in the state of contraction, which would have 

 been useful in the settlement of this supposed identity, nor as to whether the species 

 forms large or small colonies. In the example figured, upon which the above 

 diagnosis is based, there are four ultimate branches to the pedicle, the lengths of the 

 main shaft and of the two primary ramifications in both cases scarcely exceeding 

 respectively those of the extended zooids. 



Epistylis nympharum, Eng. Pl. XXXVIII. Fig. 18. 



Bodies elongate, subfusiform, about two and a half times as long as broad, 

 tapering chiefly posteriorly, and more slightly towards the anterior border ; 

 peristome somewhat oblique, its border turgid, not dilated ; ciliary disc 

 slightly elevated ; vestibular cleft developed backwards to or beyond the 

 centre of the body, exhibiting on the ventral side a knee-like flexure ; 

 cuticular surface smooth ; contractile vesicle located beneath the border of 

 the peristome ; endoplast elongate, band-like, longitudinally placed ; pedicle 

 short, smooth, or obscurely wrinkled, moderately thick, sparsely and dichoto- 

 mously branched. Length of bodies 1-166"' 



Hab. — Fresh water, on aquatic larvae ; colonies including but a few 

 zooids. 



The contour of the zooids in this species are recognized by Engelmann* as in 

 some respects resembling that of Epistylis digitalis, from which, however, it may be 

 readily distinguished by the smooth character of both the pedicle and cuticular 

 surface. 



Epistylis Steinii, Wrz. Pl. XXXVIII. Fig. 17. 



Bodies conico-campanulate, tapering posteriorly, about twice as long 

 as broad ; peristome-border thick, moderately dilated ; ciliary disc dome- 

 shaped, scarcely exsert ; cuticular surface finely striate transversely ; 

 pharyngeal cleft prolonged beyond the centre of the body ; pedicle short, 

 exceedingly thick, sparingly divided, coarsely and irregularly wrinkled 

 transversely, its diameter increasing as it approaches its junction with the 

 animalcule's body, and whose width at this point it nearly equals, per- 

 forated by a conspicuous central canal ; endoplast band-like, transversely 

 placed ; contractile vesicle situated beneath the peristome-border, on the 

 right-hand side of the vestibulum. Length of bodies 1-640" ; altitude of 

 pedicle less than that of the extended zooids. 



Hab. — Fresh water, on Gammanis pulex; colonies including but few 



animalcules. 



The short wrinkled character of the pedicle distinguishes this species from any 

 known representative of the genus; this structure, however, as remarked by 



* ' Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xi., 1862. 



