1920] Kofoid-Swezy: 31orpholocjij and Mitosis of Chilomastix 123 



is found less frequently in Chilomasti.r than in Giardia and is not so 

 readily demonstrated. In some nuclei (fig. A; pi. 15, fig. 5) the 

 chromatin is confined to a thin uniform sheet on the inner face of 

 the nuclear membrane and to the central karyosome. 



The central karyosome (fig. A, cent, k.) is a small, spheroidal 

 or angular body at or near the center of the nucleus, joined to the 

 centrosome by the intranuclear rhizoplast {int. rhiz.) and elsewhere 

 to the peripheral chromatin masses by radial linin fibers. 



The Neuromotor System 



In Trichomo-n<is the centroblepharoplast is the common point of 

 origin of all fibrillar parts of the neuromotor system and generally 

 lies close to the nuclear membrane. From it diverge the flagella, 

 marginal fibril, paradesmose, rhizoplast, and, at mitosis, the parades- 

 mose. In Chilomastix a more complex condition exists in that the 

 centroblepharoplast complex is broken up into no less than four gran- 

 ules, each giving rise to two or more outgrowths, and all connected 

 in sequence on a fiber which has its origin in the central karyosome 

 of the nucleus. 



We use the term neuromotor sj'stem here, as elsewliere (Kofoid, 

 1916; Kofoid and Swezy, 1919), to designate the integrated fibrillar 

 system uniting the karyosome, centrosome, blepharoplasts, flagella, 

 and other motor organs, and the fibers of the oral region into one 

 continuous, structural unit. In CMlmnastix this consists (fig. A) 

 of the centrosome [cent.), three blepharopla.sts {prim, bleph., sec. 

 hleph., tert. bleph.), nuclear rhizoplast {nuc. rhiz.), transverse rhizo- 

 plast {tr. rhiz.), three anterior flagella, one posterior cytostomal 

 flagellum {cyt. fl.), one parastjde {parast.), the parabasal body {par. 

 b.), and the peristomal fiber {perist. /.). Taken together these consti- 

 tute the locomotor and feeding organs of Chilmn-astix. It is not 

 improbable that the cytostomal region has also a holdfast function. 



This system is most clearly demonstrated in the encysted stage, 

 in which the cytoplasm is free from confusing and obscuring food 

 particles, and, what is far more important, the migration of the 

 nucleus from the anterior end to its median-lateral position exposes 

 the blepharoplasts and their connections. The approach of mitosis 

 permits a wider separation of the elements and a clearer inspection 

 of their structure and relations, especially of the blepharoplast com- 

 plex, the parabasal, and parastyle. It is essential to have thoroughly 



