14 DZFFLUGIA. 



with two or three points ; neck long, short or none ; 

 mouth large, terminal, circular ; lip usually straight ; 

 composed of angular quartz-sand, sometimes of diatom 

 remains, sometimes of chitinoid membrane. Sarcode 

 colorless. Common. Size : smallest specimens with shell 

 of sand, 100 fj. long by 48/* broad ; large, pyriform speci- 

 mens, 400^ long by 184// broad; largest, 520// by 

 120/et 



Hah. Ponds and ditches. 



lobostoma. SYN. : D. proteiformis, Carter, tricus- 

 pis, Carter, oblonga, Fresenius, exassula tricuspis, Ehr. , lobostoma , Leidy, 

 cremtlata, Leidy. 



Shell ovoid, oval, or nearly spherical, usually composed 

 of quartz-sand, rarely with diatoms, or of chitinoid mem- 

 brane with a few quartz particles ; mouth terminal, 

 usually three to six lobed, or more ; fundus obtusely 

 rounded. Sarcode colorless, or with green endosarc ; 

 pseudopods up to six or more. One of the most com- 

 mon species. The conjugation of two and sometimes of 

 three individuals has been observed. Size : ordinarily 

 120/* long and 100/z broad. [The shell is usually ovoid, 

 and closely resembles D. globulosa, for which it may 

 readily be mistaken unless a view of the mouth, which 

 is commonly tri-lobed, can be obtained.] 



Diffiugia arcula. 



Shell hemispheroidal ; fundus convex ; base inverted, 

 shallow infundibuliform ; mouth inferior, central, tri- 

 lobed. Shell usually of yellowish, chitinoid membrane, 

 mostly with more or less adherent dirt, or scattered par- 

 ticles of quartz-sand or diatoms, especially occupying the 



