The Microscope. 99 



fffl. Pedicle 3 to 4 times as long as the body. Social. V. alba, From. 

 Tflf. Pedicle little longer than the body, very thick anteriorly, taper- 

 ing to its posterior attachment. Social. V. crassicaulis, S. K. 

 J. Parenchyma densely granular centrally; pedicle thick, 4 to 7 



times as long as the body. Social V. campanula, Ehr. 



J. Parenchyma transparent, pale yellow ; tomato or melon-shaped 

 when contracted ; pedicle 4 to 5 times as long as the body. 



Social V. citrina, S. K. 



X. Parenchyma white; peristome border flattened, expanded, cra- 

 teriform, often frill-like; pedicle 5 to 8 times as long as the 



body. Social , V. cratera, S. K. 



%. Parenchyma transparent, colorless ; body minute, -^ Jo inch ; ped- 

 icle stout, 4 times as long as the body --- V. communis, From. 

 XX- Body conical-campanulate (||). 

 XX- Body broadly campanulate (|| ||). 



Fresh-water. One and one-fourth times as long as wide, appar- 

 ently having a thick membrane around the junction with 



the pedicle. V. aperta, From. 



Fresh-water. About as long as wide; pedicle 4 times as long as 



the minute (-g-ko) body V. communis, From. 



Salt-water, Transparent, tapering in straight lines; pedicle 3 to 



4 times as long as the body. Social V. patellina, Mull. 



Colorless, or yellowish ; oblique or pendulous, posterior extrem- 

 ity conical ; pedicle 3 to 4 times as long as the body. Social. 

 V. nutans, Mull. 

 Hyaline; pedicle decumbent, 3 to 4 times as long as the body. 



V.procumbens, From. 

 White; posterior extremity narrowly truncate; pedicle short. 

 V. dilatata, From. 



Green ; pedicle 3 to 6 times as long as the body. Social. 



V. fasciculata, Mull. 



a. Peristome small, contracted, not everted. Social. On Cyclops. 



V. globularia, Mull. 



b. Peristome with 2 to 3 nipjjle-like papillae (c). 



b. Peristome without nipple-like papillae (d). 



c. Peristome narrow, with 3 papillae V- mamillata, From. 



c. Peristome very narrow, with 2 papillae ; contracted pedicle zig- 



zag V. constricta, From. 



d. Ciliary disc small, contracted ; body ^ in. long. 



V. sphazrica. D'Udek. 



d. Ciliary disc very minute; body n\-§ in. long, enclosing refringent 



corpuscles V. margaritifera, From. 



e. Less than twice as long as broad (g). 

 e. Twice or more as long as broad (h). 



