NEBELA. 21 



CoUariS. SYN. : Difflugia collaris, reticulata, canctl- 

 lata, carpio, binodis, annulata, laxa, D. Reticella collaris, D. R. reticul- 

 lata, D. R. cancellata, D. R. carpio, D. R. binodis, D. R. annulata, D. 

 R. laxa, D. cellulifera, Ehr. ; D. peltigeracea, Carter; D. symmetrica, 

 Wallich ; D. (Nebela) numata, Leidy ; Nebela numata, Leidy. 



Shell compressed pyriform, longer than broad ; viewed 

 on broad side, fundus widely convex, sloping sides usually 

 slightly inflected toward the oral end, which is convex 

 downward ; in the narrow view oblong, fundus obtuse, 

 sometimes impressed on each side, gradually sloping, and 

 usually inflected toward the oral end, which is concavely 

 notched. Mouth transversely oval, entire. Shell color- 

 less, variable in its structural elements, generally compos- 

 ed of oval or circular disks, uniform or variable in size, 

 sometimes mingled with rod-like plates, or almost wholly 

 composed of them, rarely of thin, irregular, angular 

 plates. In some specimens the transversal section is 

 hexahedral, with concave sides and prominent, rounded 

 angles. Sarcode colorless, pseudopods digitate usually 

 3-6. Common. [A single specimen was observed by 

 Prof. Leidy, with a curved or retort-shaped shell, 150// 

 long by 72/4, and 36/* in section.] Size : usually 100;* to 

 140// in length ; average 128// long, 80^ broad, and 48, 

 thick ; mouth 32// by 24//. 



Hah. Moist sphagnum ; a constant associate of Hya- 

 losphenia papilio and elegans. 



flabettulum. SYN. : Difflugia (Nebela) fiabelliilum, 

 N . flabellulum, Leidy. 



Shell compressed pyriform or spheroid, usually broader 

 than long, sometimes not ; transverse section oval, with 

 rounded angular poles ; neck short or none ; mouth trans- 



