Abstract
A proposal is made for separation of the Ciliophora into 2 new subphyla, the RHABDOPHORA and the CYRTOPHORA based on the constancy of 2 major criteria, one morphological and the other morphogenetic. Both criteria are related to the cytostome-cytopharyngeal complex of ciliates. Comparisons are made with recently published revisions of the classification of the phylum to illustrate how the new subphyla would affect the systematic ordering of included higher taxa. Due to disturbingly sparse critical comparative ultrastructural knowledge of the Suctoria, their systematic status is the least certain, whereas other major groups appear to be placed relatively easily within the new subphyla proposed.

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