WOODRUFF: RHIZOPODA OF KANSAS. 205 



terminal in center of the truncated border. Pseudopodia very delicate 

 and transparent. 



Trinema euchelys Leidy. 



Usually the shell presents a homogeneous appearance, with a smooth 

 outline, but in the larger specimens the shells show evidence of being made 

 up of minute oval plates. The species varies greatly in size, as also in the 

 density of the material composing the shell. Some are transparent, 

 while others are completely opaque. T. euchelys is one of the smallest 

 and most abundant of fresh-water rhizopods. Its distribution is wide. 

 Plate XXXIV; figs. 51-55. 

 Centropyxis Stein. 



Shell composed of chitinous material, with the addition of sand grains, 

 diatom shells, etc., ovoid in shape, with the mouth and fundus eccentric 

 in opposite directions. Spines usually pre.sent. 

 Centropyxis aculeata Stein. 



Having characters of the genus C. may be considered as an interme- 

 diate form between Arcella and Difflugia. The color is usually some 

 shade of brown; 1 to 6 spines are usually present, which are longer and 

 more slender than those of Dif. and which seldom have any addition of 

 foreign material. Plate XXXV; fig. 60. 

 Centrpyxis ecornis. 



Shell composed of yellowish or brownish chitinoid membrane incor- 

 porated with quartz sand. Spineless mouth irregular in shape. Mouth 

 and fundus eccentric in opposite directions. Plate XXXV; fig. 61. 

 Hyalosphenia Stein. 



Shell compressed ovoid to pyriform, composed of transparent structure- 

 less chitinoid membrane; mouth terminal, inferior, transversely elliptical. 

 Sarcode mass occupying the interior of the shell to a variable extent, 

 attached to its inner surface by divergent threads and also connected to 

 the border of the mouth. Protoplasm granular, mingled with colorless or 

 colored corpuscles or both together. Nucleus large, contractile; vescicles 

 several; pseudopods few, digitate. 



Hyalosphenia papilio Leidy. 



Has characters of genus. Shell composed of transparent, yellowish 

 chitinoid membrane. Contains some green bodies. Pseudopods colorless 

 and digitate. Found in mossy ooze from golf links, Lawrence, Kan. 

 Plate XXXVI; fig. 64. 



Hyalosphenia cuneata. Found irt, connection with 64. 



Shell small, transparent, with encysted form. A large diatom shell 

 extended up through the mouth. These forms were found in green mossy 

 material collected from the gully on the golf links, Lawrence. Plate 

 XXXV; fig. 63. 

 Pamphagvs Bailey. 



Body enclosed within a transparent hyaline, elastic membrane. Endo- 

 plasm completely filling the membrane; more or less granular. A large 

 clear nucleus. Con. Vac. not distinctly determined; mouth small, terminal. 

 Pseud, long, delicate, branching but not anastomosing. 

 Pamphagus mufabilis Bailey. 



Body ovoid in shape, seldom changing form, the oval extremity more 



