1897] MICnOSCOPICAL JOUKlSAL. 145 



So far as the writer knows this is the first fresh-water 

 member of the family recorded. 



Family. — Dysteriidse. S. K. 



Genus. — Trochilia, Dujardin. 



Species. — Trochilia fluviatilis. (fig. l*!.) 

 Body subelliptical; almost twice as long as wide; cara- 

 pace single, dorsum broadly convex; anterior obliquely 

 truncate to ventrum, posterior rounded; ventrum plane 

 and clothed with fine short cilia; a movable stylate ap- 

 pendage originating in the posterior third of the ventrum 

 and projecting to a short distance beyond the posterior 

 border; projecting from, and within the anterior trun- 

 cation, are numerous fine vibratile cilia; this truncation 

 also includes the oral aperture and proceeding backward 

 from this aperture is a tubular pharynx which continues 

 directly upwards, through three fourths of the body 

 length; this pharynx is protusile; contractile vesicles, 

 three, two located in the anterior body half, above the 

 pharynx and near the dorsum and one in the posterior 

 body half below the pharynx and near the ventrum; nuc- 

 leus not observed,^obscure ; endoplsam, bluish and very 

 often vacuolar, size 1-850 inch. Habitat, Pond water 

 with aquatic plants, ponds connected with the Missis- 

 sippi river. 



For one month the writer got a number of dips from a 

 pond in Audobon Park, New Orleans, and in almost every 

 one of the numerous examinations made of this water, 

 were found an abundance of this form. They move 

 about and through debris piles very much as an Aspi- 

 disca. In no single instance, when they were examined 

 closely and measured, was there the slighest difference 

 in shape or size. While the truncated anterior was 

 pressed against a heap the tubular pharynx could be 

 seen distinctly to move forwards, as is observed in the 

 case of Entosiphon sulcatus, Duj. Unfortunately the 



