CILIATES 



179 



pattern was first explained by Ehret and Powers (1959) (Text-fig. 

 14). The present interpretation, differing only very slightly from 

 theirs, arises from a comparison of the published data on Para- 

 mecium with the later tetrahymenid studies. Cilia in Paramecium 

 arise from a boat-shaped circumciliary depression in each 



Text-figure 14. Diagrammatic reconstruction of the cortex of 

 Paramecium. Each pair of cilia emerges from the center of a polygon ; 

 the pairs of inflated alveoli defining the polygons are shown in 

 section at the right edge of the stereogram. Parasomal sacs are 

 shown adjacent to the cilia in these polygons. Resting trichocysts 

 alternate with the polygons in longitudinal rows. Kinetodesmal 

 fibers form loose cables paralleling each kinety. From Corliss 

 1961 ; redrawn from Ehret and Powers 1959. 



polygon. Trichocysts emerge from the horizontal junctions be- 

 tween polygons in a longitudinal row. As in the tetrahymenids, 

 the Paramecium pellicle consists of a continuous outer membrane 

 overlying a mosaic of alveoli, but the latter, according to all 

 accounts, are normally somewhat inflated. Furthermore, the 

 alveoli are neatly dissected into units corresponding with ciliary 



