LISTS OF FRESH-WATER RHIZOPODS. 293 



III. RHIZOPODS OBSERVED IN SLIME WITH MOSS AND ALG.E SCRAPED 

 FROM THE VERTICAL FACE OF DRIPPING GNEISS ROCKS OF 

 FAIRMOUNT RESERVOIR, PHILADELPHIA, JULY 0, 1S79. 



1. Difflttgia constkicta. Occasional, and merging into forms which might be 



equally well viewed as the variety Ccntropyxis ecornis; 0.09 mm. long, 0.07S mm. 

 broad, and with mouth 0.03G mm. wide. An unusually long specimen was 0.12 

 mm. long, 0.072 mm. in the greater and 0.054 mm. in the less breadth. When 

 the mouth was on a level it stood 0.0G mm. high. All specimens of a yellowish 

 hue. 



2. Centropyxis aculeata." Small, of yellowish chitinoid membrane incorporated 



with sand, and usually with two or three spines. Length 0.072 mm.; breadth 

 0.00 mm. ; width of mouth 0.03 mm. 



3. EuGLYPnA alveolata. Small, spineless form ; abundant. Shell ovoid; trans- 



verse diameters uniform, rarely slightly compressed ; fundus obtuse, rarely in 

 the smallest acute ; mouth with 4, G, or 8 teeth, the rnnnber not in accordance 

 with size. More dead shells than living specimens ; many with the sarcode 

 apparently resolved into spores, which were shining, oil like globules, from one 

 or two to half a dozen or more in number, and of pretty uniform size, being 

 about 0.012 mm. Specimens mostly 0.0GG mm. to 0.072 mm. long, 0.03G mm. to 

 0.042 mm. broad, and 0.01S mm. wide at the mouth. Ranging from 0.033 mm. 

 to 0.01) mm. in length, by 0.012 mm. to 0.042 mm. in breadth. Nucleus of the 

 sarcode about 0.018 mm. Variety: several dead shells with the mouth oblique 

 or subterminal; 0.0G mm. in length, 0.03G mm. in breadth, and 0.0135 mm. wide 

 at the mouth. Variety: with a slight curvature approaching the mouth. A 

 bving specimen 0.0G mm. in length, 0.03G mm. in breadth, and 0.012 mm. wide 

 at the mouth. 



4. Euglypiia ciliata. One living specimen observed. Shell ovoid, compressed, 



with three spines to one side, two to the other, and one to the fundus ; mouth 

 with four thickened teeth. Length 0.0G mm.; greater breadth 0.024 mm.; at 

 mouth 0.009 mm. Resembled fig. 14, pi. xxxvi. 



5. Trinema enchelys. Mostly dead shells, small, and frequent. The cancellated 



structure not visible in the smaller but distinct in the larger ones. From 0.03 

 mm. to 0.078 mm. in length, 0.012 mm. to 0.042 mm. in breadth. Several with 

 the sarcode encysted, and several with the latter resolved into spores. A pair 

 of empty shells, observed adhering mouth to mouth, as in conjugation, and dis- 

 posed in the same direction, and not in opposite directions as previously noticed. 

 One of the shells 0.042 mm. long, the other 0.03 mm. long. 



6. Actexopiirys sol. Occasional; in active condition. A pair observed either in 



conjugation or act of division. 



7. Amceba radiosa. Few. 



8. A. VERRUCOSA. Young condition as A. quudrilineata. 



9. A. proteus? Young. Occasional. 



