New American Infusoria. By Dr. A. C. Stokes. 703 



Hymenonema (vfJ'Vv, membrane ; vrj/xa, thread), gen. nov. 



Animalcules free-swimming, inhabiting a flexible, membranous 

 lorica, and inclosing two laterally developed pigment-bands ; flagellum 

 single ; no eye-spot. Habitat : Fresh water. 



The presence of but one flagellum is the only distinguishing 

 feature between the animalcules of this generic group and the 

 Eymenomonas of Stein. The lorica apparently possesses the same 

 pecuharity of flexibility and the power to somewhat change its contour 

 as are possessed by Hymenomonas. 



Hymenonema Sphagni, sp. nov. 



Lorica ovate, flexible and slowly changeable in form, often less 

 than twice as long as broad, the entire surface covered with rounded, 

 shallow depressions ; inclosed zooid entirely filling the cavity of the 

 lorica; colour-bands yellowish-brown, broad, almost meeting in the 

 centre of the body ; flagellum single, shorter than the lorica, its distal 

 end usually arcuately curved ; contractile vesicle single or double, 

 situated at the anterior extremity ; a refractive corpuscle usually 

 conspicuously developed in the anterior body-half, near the centre of 

 one lateral border. Length of lorica 1/750 in. Habitat: Pond 

 water with Sphagnum. 



Hymenomonas jiava, sp. nov. Fig. 23. 



Lorica ovate, punctate, twice as long as broad, very slightly 

 flexible, the posterior extremity rounded, the anterior prolonged into 

 a short, inconspicuous, neck-like extension, the frontal margin trun- 

 cate ; body filling the entire lorica except the neck-like prolongation ; 

 endoplasm yellow, inclosing numerous granules; contractile vesicle 

 apparently single, antero-terminal ; flagella not equalling the lorica 

 in length, usually only one-fourth as long. Length of lorica 

 1/1125 in. Habitat : Standing pond water, with decaying Sphagnum. 



Hymenomonas fusiformis, sp. nov. Fig. 24. 



Lorica subfusiform, less than four times as long as broad, widest 

 centrally, the anterior border pointed, the posterior extremity obtusely 

 and narrowly rounded; the body usually filling the entire lorica, 

 but often somewhat removed from both extremities of the sheath ;. 

 endoplasm yellow ; contractile vesicle double, small, near the anterior 

 extremity ; nucleus obscure, apparently subcentrally located ; flagella 

 about one-half as long as the lorica. Length 1/690 in. Habitat : 

 Standing pond water, with Sphagnum. Movements rotatory on the 

 longitudinal axis. 



Zygoselmis ohovata, sp. nov. Fig. 25. 



Body normally elongate obovate, about seven times as long as 

 broad ; anterior extremity obtusely pointed, the posterior rounded ; 

 flagella diverse, the longer subequal to the extended body in length. 



