6l8 ORDER HETEROTRICHA. 



long, stout, widely separated cilia, and an inner spiral wreath of fine, closely- 

 set shorter ones ; cilia of the general cuticular surface short and fine, 

 arranged in widely separated longitudinal rows ; endoplast linear, curved, 

 anteriorly located ; contractile vesicle situated at a short distance from the 

 posterior extremity. Dimensions unrecorded. 

 Hab. — Salt water : Baltic Sea. 



According to Stein's observation the animalcules of this species become readily 

 detached from their loricfe, and withdrawing the stem portion within the general 

 substance of the body, swim freely in the water. The outer circle of long and 

 widely separated peristomal cilia was frequently observed to be flexed backwards, 

 reaching at such times to a distance of one-third of the total length of the body from 

 the posterior extremity. These structures in their great length and flexibility would 

 appear to closely resemble the tentaculiform cilia of Codonella and Didyocysta, 

 the lorica at the same time closely corresponding with that of Codonella campanella. 

 The specific title bestowed on this type by its discoverer bears reference to the 

 superficial likeness of the surface bands of cilia in both aspect and distribution 

 to those of a Beroe. 



Fam. VII. CALCEOLID-ffi, S. K. 



Animalcules free-swimming, illoricate, ovate or pyriform, persistent 

 in shape ; general cuticular surface entirely ciliate, the body encircled by 

 one or two zone-like grooves and girdles of larger cirrate cilia; the oral 

 aperture ventral, perforating one of the equatorial grooves of cilia ; a 

 closely adpressed fascicle of long flexible setose cilia, presenting the aspect 

 of a stylate caudal appendage, projecting backwards from behind the 

 oral aperture. 



Genus I. CALCEOLUS, Diesing. 



Animalcules free-swimming, unsymmetrical, obliquely pyriform, per- 

 sistent in shape, but not encuirassed; cuticular surface finely ciliate 

 throughout, two groove- like channels encircling the body, one or both of 

 which give origin to a wreath of larger cilia than those of the cuticular 

 surface ; oral aperture ventral, situated in the posterior of the two trans- 

 verse annular grooves, followed by a tubular pharynx ; a tail-like fascicle 

 of long setose cilia, usually held bound to one another, and resembling a 

 single stylate process, projecting backwards from behind the mouth ; endo- 

 plast and contractile vesicle posteriorly located. 



This genus is instituted by Diesing * for the form described that same year by 

 Professor H. James-Clark under the title of Pcridinium cypripediiim. Regarding, in 

 common with the last-named authority, the fascicle of setose cilia forming the caudal 

 appendage as an ordinary flagellum, Diesing has placed his newly created genus 

 among other Cilio-flagellate animalcules midway between Mallomonas and Proro- 

 centriim. From this low position in the infusorial scale it is here proposed to 

 advance it to one among the Heterotricha corresponding closely with that occupied 

 by Urocentrum in the division of the Peritricha. 



* ' Revision der Prothelminthen,' p. 379, 1865. 



