340 University of California Publications in Zoology [Vol. 18 



description of the genus. Stein (1859) gave several pages to a con- 

 sideration of the systematic position of the genus and described a few 

 of the different species. Likewise Kent (1881) gave a mere synoptic 

 account of the genus and its species. Maupas (1883) mentions seeing 

 some fibers extending anteriorly from the anal cirri in an unnamed 

 species of Euplotes. In later works (1886-1889) he considers the 

 process of conjugation in Euplotes patella. Schuberg (1899) gave a 

 short account of the process of division of this species. Wallengren 

 (1901) contributes a rather full account of the formation and resorp- 

 tion of cirri in dividing individuals of E. liarpa and also considers 

 the origin of the new cytostome, while Prowazek (1903) describes 

 the same species and gives special reference to a system of fibers which 

 he finds in connection with the cirri. Griffin (1910) in two papers' 

 describes a new species, E. ivorcesteri, in which he gives a rather 

 detailed description of certain parts including a fibrillar system in 

 connection with the cirri, and of the division process. Other than the 

 above mentioned works little seems to have been written about this 

 group of highly specialized ciliates. 



In this study of Euplotes patella it is the purpose to give a general 

 description of the anatomy of the animal, and a detailed description 

 of the system of fibers in connection with the cirri and membranelles. 

 This system will be described as the neuromotor apparatus and an 

 attempt will be made to show in what way it may be considered as 

 having the function of a primitive nervous system. A description will 

 also be given of the division process, with special consideration of 

 the nuclear phenomena and the formation of the new neuromotor 

 apparatus in each of the daughter organisms. An attempt will also 

 be made to show that the neuromotor apparatus of flagellates is 

 homologous with that structure found in ciliates. 



Acknowledgments 



This work was started in the winter of 1915 under the direction of 

 Dr. Olive Swezy, to whom I wish to express my sincere thanks for her 

 aid and encouragement in beginning this work. Especially do I wish 

 to express my gratitude to Professor C. A. Kofoid for his many helpful 

 criticisms and suggestions during the last year of the work. 



