CILIATA 



99 



bedded in the cortex. Either the cortex or both it and the alveolar 

 layer may be absent. In Paramecium the cortex is covered by a thick 

 pellicle which possibly contains a minute alveolar layer. 



rid. tri. fH 



Fig. 84. Details of the ectoplasm of ciliates. After Wetzel. A, Frontonia leucas 

 (Vestibulata). B, Paramecium. C, The same, surface view. afo. alveolar layer; 

 ba.gr. basal granules; cor. cortex; enp. endoplasm ; y?. flagellum ; yZ.' insertion 

 of flagellum ; pel. pellicle ; rid. ridges of pellicle ; tri. trichocyst. 



Order HOLOTRICHA (ASPIRIGERA) 



Ciliata which do not possess an adoral wreath ; and which nearly all 

 have uniform ciliation of the whole surface of the body. 



This order is a collection of relatively simply organized ciliates, 

 some of which are primitive while others are degenerate through 

 parasitism. 



Suborder PROCILIATA 

 Holotricha without mouth ; and without differentiation of meganuclei 

 from micronuclei. 



Opalina{Figs.^, 21 0,85). With several, usually many, nuclei, which 

 are all alike. In each nucleus, however, there can be distinguished 



Fig. 85. Opalina ranarum. From Borradaile. A, Ordinary individual in 

 longitudinal fission. B, The same in transverse fission. C, Small encysted 

 individual (distributive phase). D, Gamete. E, Encysted zygote. 



7-2 



