12 DIFFLUGIA. 



rarely inverted. Shell composed of quartz-sand, diatoms, 

 or of chitinoid membrane with sand and diatoms. Sar- 

 code, apart from food, colorless. Size : smallest, with shell 

 of sand, 36/j. long by 30^ broad, mouth 15 p. wide ; chiti- 

 noid specimens, 24// to 108/* long by 32/* to 120// broad. 

 Hob. In the ooze of ditches and ponds, or on moist 

 earth in bogs, among mosses, etc. 



pyriformis. SYN.: Difflugia, Leclerc, Carter; 

 D. pyriformis, Perty, Ehr., proteiformis, Lamarck, Ehr., Wallich, 

 compressa, Carter, entochloris, Leidy, vets, Leidy, nodosa, Leidy, 

 cornuta, Leidy. 



Shell pyriform, flask-shaped or ovoid, with narrow pole 

 prolonged into a neck of variable length, circular or 

 somewhat compressed ; fundus obtusely rounded or sub- 

 acute or produced into one to three conical processes. 

 Neck gradually and evenly narrowed to the oral end, 

 cylindroid, sometimes constricted, mouth inferior, termi- 

 nal, circular or oval. Shell usually composed of angular 

 particles of quartz-sand mingled with diatoms. Sarcode 

 bright green, from chlorophyll grains. Common. The 

 form of the shell varies greatly from pear-shaped to flask- 

 like, the body gradually prolonged into a cylindroid or 

 tapering neck. Size : 60/* to 580^ long by 40/* to 240/z 

 wide ; mouth 16// to 120// wide. 



Hob. Ooze of ponds, ditches and bogs. 



Variety I. D. pyriformis. 



Variety II. D. compressa, laterally compressed. 

 Variety III. D. nodosa, fundus with eminences. 

 Variety IV. I). cor?iitia, fundus with conical pro- 

 cesses. 



Variety V. D. vas* neck defined by a constriction. 



