EDMONDSON — PROTOZOA OF IOWA. Ill 



taken from the ice-water were and probably had been for a long 

 time in a state of inactivity. 



On fixing and staining these individuals it was found that the 

 macrosomes were conden,sed into rounded masses, usually from 

 six to twelve being arranged in a median row throughout the 

 length of the nucleus. Moreover, the macrosomes were highly 

 vacuolated, Figure 196 being drawn from a permanent prepara- 

 tion. 



It is probable that these individuals, taken from such an envi- 

 ronment as they were, had received little or no nutrition for some 

 time, the physiological result of this loss being manifested in the 

 vacuolated and more fluid condition of the macrosomes. 



Sometimes Carcheshim polypi7ium is the temporary host of Am- 

 phileptus nieleagris, as before described. The habitat of Carche- 

 shun polypuiiun is fresh water, often being found in running 

 streams, attached to the under side of rocks, leaves, etc. 



EPISTYLIS Ehrenberg. 



Zooids somewhat similar to Vorticella, usually forming a dicho- 

 tomously branched colony, with a stout non-contractile stalk. 



Epistylis flavicans Ehr. 



Zooids campanulate, greatly dilated anteriorly when extended. 

 Five or six circles of strong cilia about the ciliary disk. Stalk 

 dichotomously branching and rigid, at least in the young forms. 

 Bodies usually pale yellow in color, transversely striate. Nucleus 

 band-like, curved. 



Length of zooids, 200-350 microns. 



The zooids of this species are among the largest and perhaps 

 the most strongly ciliated of the genus. 



Figure 202, Plate XXVIII, illustrates a colony with a rigid, 

 erect pedicle, and but two zooids, which indicates a very young 

 stage. In old forms the stalk loses its rigidity and the whole 

 colony falls down in a tangled mass. Kent reports that lack of 

 food will transform an erect colony into a decumbent one within 

 a few hours, and specimens taken from fresh water near Iowa 

 City in the early winter were all in this condition, probably due 

 to the same cause. 



Reproduction by longitudinal fission continues even after the 



