146 University of California Publications in Zoology [Vol. 20 



nomenclature of these organisms be established upon as sound a basis 

 as may be feasible with our present knowledge of the organisms and 

 in the light of the accumulated literature, much of which is confusing, 

 incomplete, and even contradictory. 



The early microscopists who first explored the invisible living world 

 turned their crude in.struments to the dejecta of man and found therein, 

 as elsewliere in organic material in the early stages of decay, a horde 

 of bacteria and of flagellates feeding thereon. They were hampered 

 in their investigations by the rapid movements of the monads, by 

 the fact that the technique of modern staining was undeveloped, by 

 the poor definition of their lenses which failed to reveal the number 

 and relation of the flagella. by the lack of organization of scientific 

 bibliography, and by the absence of monographic works. The science 

 of protozoology was, as yet, undeveloped. 



These observers saw the commoner flagellates of man, sketched and 

 described them briefly and imperfectly, especially as to the flagella 

 which now constitute the bases of classification. They often mis- 

 interpreted the undulating membrane as a row of cilia, and either 

 failed entirely to see the other flagella, or did not correctly resolve 

 their numbers. Added to these difficulties is the fact that clinicians 

 and zoologists have each alike been uninformed, in many cases, as to 

 the literature in the other's field when they have ventured to christen 

 some newly discovered flagellate from the intestine of man. 



As a result of these conditions the nomenclature of these flagellates 

 has been in a continual state of confusion from the early discoveries 

 of Miiller (1773), Donne (1837), Davaine (1854, 1860, Lambl (1859, 

 1875), and Grassi (1879, 1881) to the present time. 



After some experience at the U. S. Army Laboratory, New York 

 City, and in the Division of Parasitology, Bureau of Communicable 

 Diseases, California State Board of Health, of the practical difficulties 

 in the identification of intestinal flagellates with existing facilities, and 

 a persistent effort to establish on sound bases the names at present 

 widely but not universally used for these organisms, and after a 

 careful perusal of the pertinent literature, the following conclusions 

 are offered as a solution of the correct nomenclature, under the 

 Zoological Code of Nomenclature, of the common flagellates of man. 

 We offer our , conclusions for criticism, with the hope that they may 

 be recognized as conforming to the Code of Nomenclature, and that 

 they may conduce ultimately to stability of nomenclature in this 

 common ground of medicine and zoology. 



