Sex in Protozoa 



A Comparatioe Reu/eiu 



D. H. WENRICH, Zoological Laboratory, 

 University of Pennsylvania, Philadelphia 



In planning the symposium, it seemed especially important to in- 

 clude the highly interesting sex phenomena in the flagellates living 

 in the intestine of the wood-feeding roach, Cryptocercus pimcudatuSy 

 being worked out by Cleveland, and the latest developments in our 

 knowledge of mating-type behavior in Faravieciwn. Since these pa- 

 pers could cover only a small fraction of the subject of sexual repro- 

 duction in the Protozoa, it seemed desirable to offer a review of 

 sexuality in the group as a whole. In preparing the material for pub- 

 lication, the coverage presented at the symposium has been expanded. 

 Unfortunately, Dr. Cleveland did not find it possible to provide a 

 discussion of his results for the volume; hence I have added a con- 

 densed review of his published papers on this subject to the discussion 

 of the Mastigophora. 



In addition to such general works on Protozoa as those of Kent 

 (1880-82), Biitschli (1882-89), Minchin (1912), Wenyon (1926), 

 Calkins (1933), Kudo (1946), Grasse (1952-53), and Hall (1953), 

 the reviews of Jennings (1920), Belar (1926), Calkins and Summers 

 (1941), Hartmann (1943), Doflein and Reichenow (1949-53), and 

 Luyet (1950) are useful as references. For many of the major groups 

 of Protozoa our knowledge of sexuality is very scanty, but for others 

 there is an extensive literature. References to the literature in this 

 review are therefore selective rather than comprehensive. In general, 

 the sequences of classes and orders as given in Kudo's Protozoology 

 (1946) will be followed. Kudo divides the Phylum Protozoa into two 

 subphyla, the Plasmodroma and the Ciliophora. The Subphylum Plas- 

 modroma is separated into the classes Mastigophora, Sarcodina, and 

 Sporozoa, which will be discussed in that sequence. 



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