Organisms Consisting of One Cell 



255 



ditioii oi' tliis protist is not merely a stage in the life history of 

 the organism. No uni-niicleate stage occurs and the creatnre is 

 typically organized on tlie binucleate plan. It should be noted 

 that the two nuclei are alike mor))liologically and ])resumably 

 physiologically, so they do not correspond to the macro- and 

 micro-nuclei of some ciliates. The animal may consequently be 



anfchlosmu. 



i-nffocut.la+.fl- 



^ cyt.- - - 



XTUCt - 



cary.halox- - 



cartjr - - 



post perisjK - - 



por.if-- - 



tri.halo.-- - - 



ax 



pos 



lb 



as. 



anLVialo 



- -anf. per-is^ 

 l.blfepH. 



cen-t. 



tn'tf QTtuc. rhir 



lat. bQs.g-r. 



--ant. Iat.f1. 

 --r£ir. vent.f 1. 



post. lat. f 1. 

 tjost. t1. 



FIGURE 9. GIARDIA MURIS (aFTER KOFOID AXI) ClIRISTI AXSE X ) . 



ant. chiasma, anterior chiasnia. ant.halo., anterior halo, ant.lat.fl., 

 anterior lateral flagellum. ant.perist., anterior peristome, ax., axo- 

 style. cary., karyosome. cary.halo, karyosonial halo, cent., centre- 

 some, cyt., cytostome. fr.vent.fl., free ventral flagellum. intraeyt.- 

 lat.fl., intracytoplasmie part of the postero-lateral flagellum. intra- 

 nuc.rhiz., intranuclear rhizoplast. lat.bas.gr., lateral l)asal granule, 

 post.fl., posterior flagellum. post.lat.fl., posterior lateral flagellum. 

 post.perist., posterior peristome, l.bleph., left blepharoplast. rhiz., 

 rhizoplast. tri.halo., triangular halo. 



justly regarded, as Kofoid and Christiansen remark, as the 

 "simplest (from the standpoint of numbers only) possible multi- 

 nuclear organisms." ^* Special notice should also be taken of the 

 hlepharoplasts (1. bleph.), the axostyle (ax.) and the parabasal 

 bodies (par. b.) 



Worthy of mention is the fact that this system of organs, 

 called by the authors the neuromotor system, is so well differen- 

 tiated from the rest of the body sub^tanpe, and so pernianent 



