CILIATE PROTOZOA (INFUSORIA) 



297 



203 (204) Without an operculum. Zooid like Thuricola; adherent to the 

 bottom of the lorica in a sessile manner or united by a con- 

 tinuation of the supporting pedicel. . Cothurnia Ehrenberg. 

 Representative species Cothurnia plectostyla Stokes 1885. 



Lorica curved, two and one-half times as long as broad, finely striate 

 longitudinally, also with transverse markings. Divided posteriorly 

 into two unequal parts by a curved, chitinous partition to which the 

 zooid is attached. Zooid not protruding much beyond the aperture 

 when extended; transversely striate. Length of lorica no pi. Marsh 

 water. 



FIG. 549. Cothurnia plectostyla. cv. contractile vacuole; macn, macronucleus . 

 X 250. (After Stokes.) 



204 (203) With an operculum of chitin developed beneath the peristome and 

 closing the lorica when the animal is retracted. 



Pyxicola Kent. 

 Representative species. Pyxicola carteri Kent 1882. 



Lorica subcylindrical, three times as long as broad, anterior margin 

 slightly oblique, walls undulate. Pedicel very short. Zooid extending 

 beyond the aperture. Length of lorica oo p. Fresh water. 



FIG. 550. Pyxicola carteri. X 270. (After Kent.) 



205 (198) Lorica decumbent. . . , 206 



206 (207) Animal adherent to the posterior extremity of the lorica. 



Platycola Kent. 

 Representative species Platycola decumbens Kent 1882. 



Lorica oval, depressed. Zooid extending considerably 

 beyond the aperture, the exserted portion being at right 

 angles to the portion within the lorica. Length of lorica 

 90 M- Fresh water. 



FIG. 551. Platycola decumbens. X 200. (After Kent.) 



207 (206) Animal adherent to one side of the lorica which often has a valvular 

 aperture. Zooid adherent to the margin of the aperture. 



Lagenophrys Stein. 

 Representative species. . . . Lagenophrys vaginocola Stein 1851. 



Lorica elongate with two semilunar, lip-like processes partially closing the 

 aperture. The processes are raised when the zooid is extended and lowered 

 when it is retracted. Zooid adherent by its narrow peristome to the edge of 

 the aperture. Length of lorica 70 n. Fresh water. Stylohedra Kellicott differs 

 from Lagenophrys in having an erect lorica with a pedicel. 



FIG. 552. Lagenopkrys vaginocola. X 210. (After Maupas.) 



