GENUS STICHOTRICHA. 775 



bordering the attenuate caudal prolongation ; contractile vesicle situated 

 towards the posterior end of the thicker central region. Length I-250". 

 Hab. — Salt water. 



The abnormal size of the five radiating frontal styles, which in this respect closely 

 resemble those of Actinotricha saltans, in addition to the less attenuate contour of the 

 anterior extremity, suffices to distinguish this animalcule from the two preceding types. 

 As originally described and figured by Quennerstedt,* that authority, apparently 

 unaware of Stein's new generic appellation, has proposed to confer upon it the title 

 of Mitra radiosa. Even in the absence of this prior title, Quennerstedt's suggested 

 name of Mitra could not, however, have been retained, it having been long since 

 preoccupied for the distinction of a genus of the Mollusca. 



Genus X. STICHOCH^TA, C. & L. 



Animalcules free-swimming, elastic but not contractile, the anterior 

 extremity attenuate and neck-like ; a row of long peristomal cirrose cilia 

 extending backwards from the apical extremity to the oral aperture which 

 lies at the base of the neck-like prolongation ; a border of small marginal 

 setae and two or three ventral rows of similar ventral setae usually present ; 

 a group of long slender anal styles developed at the posterior extremity. 



The author retains as the type of this genus the Stichochata pediailiformis of Cohn,f 

 which differs essentially from the several specific forms of Sticholricha, with which it 

 otherwise closely corresponds, through its possession of well-developed anal styles. 

 The StkhochcEta cormitum of Claparede and Lachmann is rightly referred by Stein 

 to the last-named generic group. 



Stichochaeta pediculiformis, Cohn. Tl. XI J V. Figs. 13 and 14. 



Body linear-oblong, rounded posteriorly, flexible but not retractile, the 

 anterior third produced as a narrower neck-like process, and bearing at its 

 summit about six long, movable setae, a spiral row of similar sets extend- 

 ing backwards from these to the oral aperture ; a row of short, fine marginal 

 setae developed down each lateral border of the ventral surface, and between 

 these three rows of short ventral setae ; five long, slender anal styles, disposed 

 in two groups of three and two each, at the posterior extremity ; oral aper- 

 ture situated at the base of the neck-like prolongation, having issuing from 

 it a bundle of several long, flexible oral cilia ; contractile vesicles two in 

 number, one located near the oral aperture and the other towards the 

 posterior extremity; parenchyma very opaque, through the enclosure of 

 innumerable fat-like corpuscles. Length 1-250". 



Hab. — Salt water. Movements alternately creeping and springing 

 backwards. 



Genus XL STICHOTRICHA, Perty. 



Animalcules elongate, elastic, and changeable in form, the anterior ex- 

 tremity attenuate and neck-like ; peristome-field narrow, fissure-like, extend- 



* ' Bidrag til Sveriges Infusoriefauna,' Heft ii., 1867. 



t " Neue Infusorien im Seeaquarium," 'Zeit. Wiss. Zoo!.,' Bd. xvi., 1866. 



C 



