EDMONDSON — PROTOZOA OF IOWA. IO9 



VoRTicKLLA Fi.uviATiLis From. 



Body ovate, truncate anteriorly, with a deep concave depression 



in the anterior border, where the stalk is produced. Surface 



smooth. Stalk three or four times the length of the body. 

 Length of body, 40 microns. (Fig. 186, PI. XXVI.) 

 Habitat, fresh water. Solitary in habits. Observed in Keokuk 



county. 



VORTICELLA CONVALLARIA Linn. 



Body elongate, twice as long as broad, conical, slightly dilated 

 anteriorly. Surface transversely striate. Stalk four or five times 

 as long as the body. 



Length of body, 100 microns. (Fig. 190, PI. XXVL) 

 Social in habits. Found in infusions of pond water. The ped- 

 icle of this species is frequentl}^ the support for the collared flag- 

 ellate, Mojwsiga steinii. 



VORTICELLA ELONGATA From. 



Body elongate, two and one-half times as long as broad, wider 

 anteriorl}', with margin slightly dilated. Surface transversely 

 striate. Stalk short, not often more than twice the length of the 

 body. 



Length of body, 80 microns. (Fig. iSy, PI. XXVI.) 



Habitat, stagnant water. Solitary in habits. 



VORTICELLA Sp. 



Figure 193, Plate XXVI, illustrates a very small species of \'or- 

 ticella sometimes found in this state. 



Body elongate ovate, wider centrally, anterior border slightly 

 dilate. Tapering from the middle to the narrow posterior extrem- 

 ity. Surface smooth. Endoplasm transparent. Stalk slender, 

 about three times the length of the body. 



Length of body, 30 microns. 



Habitat, stagnant water. Solitary. 



CARCHESIUM Ehrenberg. 



Resembling Vorticella but forming branched colonies with a 

 common pedicle, the central muscle fibre being interrupted at the 

 union of the stalk of each zooid and the branch allowing the zooid 

 and its pedicle to contract independently. 



