388 ORDER FLAGELLATA-EUSTOMATA. 



flagellum, succeeded posteriorly by a slender pharyngeal passage; endoplasm 

 coloured green, generally enclosing an anterior eye-like pigment-spot ; 

 contractile vesicle and endoplast conspicuous. Inhabiting fresh water. 



So far as it is possible to determine from the figures, with their accompanying 

 indices, given by Stein,* the members of this genus are to be distinguished from 

 those of Phacus by the presence only of the conical anterior prolongation which is 

 perforated at its apex by the oral aperture. In all other respects the two appear to 

 essentially agree. 



Chloropeltis hispidula, Eichwald sp. PL. XXI. FIGS. 8 AND 9. 



Body broadly ovate, compressed, nearly as broad as long ; caudal pro- 

 longation straight or slightly curved, equalling one-third of the length of 

 the body ; cuticular surface longitudinally ribbed, each rib thickly hispid 

 throughout ; an anterior eye-like pigment-spot usually developed ; the 

 contractile vesicle situated close to the termination of the pharyngeal 

 passage, and apparently communicating with it ; endoplast ovate, posteriorly 

 located. Length 1-500". HAB. Fresh water. 



The general contour of the body of this species coincides remarkably with the 

 flattened and longitudinally ribbed fruit of various Umbelliferous plants, and more 

 especially perhaps with that of the common parsnep, Pastinaca ; it was originally 

 described by Eichwald \ as a species of Euglena. As figured in Stein's recent 

 work, the number of longitudinal hispid ribs is shown to vary considerably in 

 different individuals. In some there are only half-a-dozen upon each flattened side, 

 while in others there may be as many as or more than twice that number. 



Chloropeltis ovum, Ehr. sp. PL. XXL FIGS. 11-13. 



Body somewhat variable in form, mostly symmetrically elliptical and 

 cylindrical, but sometimes subspheroidal or subfusiform ; caudal prolonga- 

 tion short, acuminate ; cuticular surface usually finely striate in an oblique 

 but more exceptionally in a longitudinal direction ; anterior conical projec- 

 tion conspicuously developed ; endoplasm often enclosing two large or 

 four smaller, circular, bilaterally corresponding, amylaceous corpuscles- 

 Length 1-1500" to 1-640". HAB. Fresh water. 



This species was first described by Ehrenberg under the title of Euglena ovum. 

 Stein proposes to identify the more attenuate, fusiform variety with the Euglena 

 zonalis of Mr. Carter. 



GENUS V. TRACHELOMONAS, Ehrenberg. 



Animalcules monoflagellate, plastic and changeable in form, enclosed 

 within a free-floating, ovate or spheroidal, indurated sheath or lorica, the 

 anterior extremity of the lorica perforated by a minute aperture, through 

 which in its normal condition the single flagellum only is protruded ; oral 

 aperture terminal, followed by a distinct pharyngeal passage endoplasm 

 coloured green, with usually a red pigment-spot at the anterior extremity ; 

 contractile vesicle single, spherical, located near the anterior pigment-spot. 

 Mostly inhabiting fresh water. 



* ' Infusionsthiere,' Abth. iii., 1878. t ' Infusoria Russlands,' 1847. 



