700 ORDER PERITRICHA. 



same Ehrenbergian species, both of which possess a broadly campanulated contour 

 altogether distinct from the present type. Only two animalcules constitute the 

 colony-stock of this species as figured by De Fromentel, their aspect correspond- 

 ing most nearly with that of two abnormally united VorticellcE. 



Zoothamnium marinum, Mereschk. Pl. XXXVI. Fig. ii. 



Bodies conical, campanulate, somewhat gibbous, pyriform and evenly- 

 puckered anteriorly when contracted ; the peristome-border dilated and 

 obliquely truncate ; the ciliary disc moderately elevated ; pharyngeal cleft 

 conspicuously developed ; cuticular surface entirely smooth ; parenchyma 

 finely granulate ; endoplast ovate, minute ; pedicle neither striate nor 

 articulate, branching in a perfectly even dichotomous manner, supporting 

 from four to eight or twelve animalcules only. Length of bodies (in spirit) 

 1-240". 



Hab. — Salt water : White Sea (Mereschkowsky), attached to seaweeds 

 and zoophytes at depths of from 5 to 12 fathoms. 



A species apparently allied to, if not identical with, this type has been obtained 

 by the author at St. Heliers, Jersey, attached to the carapace and setose appendages 

 of the common shore-crab Caninus 7?icEnas, and will be found figured at PI. 

 XXXVII. Figs. 17-20, in connection with the provisional title of Zoothamfiiiwi 

 carcini. 



Zoothamnium simplex, S. K. Pl. XXXVI. Figs. 17-20. 



Bodies when extended elongate-conical, the anterior border widest, 

 tapering gradually thence to the attenuate posterior extremity, from three 

 to four times as long as broad ; pyriform when contracted ; stationed in a 

 single cluster of seldom more than half a dozen zooids at the extremity of 

 a simple, unbranched, rarely and slowly contracting pedicle, whose altitude 

 equals about twice the length of an extended zooid ; ciliary disc moderately 

 elevated above the peristome-border ; cuticular surface smooth, finely 

 granular ; endoplast elongate, attenuate, longitudinally placed. Length of 

 extended bodies 1-300". Hab. — Pond water. 



This species was obtained by the author in November 1880, attached in some 

 abundance to the leaves oi Myriophylluin and other aquatic plants growing in a fresh- 

 water aquarium, its original derivation being uncertain. The disposition of the animal- 

 cules in a single group at the extremity of a simple pedicle distinguishes it con- 

 spicuously from all known representatives of the genus, the elongate contour of the 

 bodies, at the same time, while differing from all members of the allied genera 

 Zoothamnium and Canhcsium, closely resemble those of Epistylis plicatilis. The 

 pedicle, as in Carchesinm cpistylidis, is remarkable for its rare and sluggish contrac- 

 tion. In one instance, as represented at Pl. XXXVI. Fig. 20, the conjugation of a 

 minute migrant and normal sized sedendary zooid was observed. 



Genus X. EPISTYLIS, Ehrenberg. 



Animalcules campanulate, ovate or pyriform, corresponding structurally 

 with those of Vorticella, attached in numbers to a rigid, uncontractile, more 

 or less branching, tree-like pedicle or zoodendrium ; the zooids usually of 

 similar size and shape. Inhabiting salt and fresh water. 



