1922] Kofoid-Sivezy : Mitosis and Fission in Giardia enterica 203 



relatively greater thau this in living individuals. The tail is conical 

 (25°-30°), concave laterally near the base in dorsal view, tapering to 

 a blunt point, and is about 0.6 to 0.7 transdiameter in length. Its 

 ventral surface is flattened and continuous with the flattened area 

 between the posterolateral flagella. In life it is very mobile. It ter- 

 minates in the posterior flagella proceeding from the axostyles. 



intracyt. lat. fl. 



Fig. A. Lateral view of Giardia enterica (Grassi). Fig. B. Ventral view. 

 Fig. C. Cyst with 2-zooid individual. Abbreviations: ant. node, anterior 

 node; ant. perist. /., anterior peristomal fiber; ax., axostyle; bleph., blepharoplast; 

 Tcary., karyosome; cent., centrosome; cyst., cyst wall; cyt., eytostome; intracyt. 

 lat. fl., intracytoplasmic lateral flagella; intracyt. post. lat. fl., intracytoplasmic 

 posterolateral flagella; intranuc. rliis., intranuclear rhizoplast; lat. fl., lateral 

 flagella; nuc, nucleus; par., paradesmose; par. h., parabasal; par. h. rhig., para- 

 basal rhizoplast; post, fl., posterior flagella; post, perist. /., posterior peristomal 

 fiber: rhiz., rhizoplast; trans, comm., transverse commissure; vent, fl., free ventral 

 " " X 2260. 



The structures found in the body (figs. A and B) are two nuclei 

 {nuc), the eytostome {cyt.), and the neuromotor apparatus consisting 

 of the two axostyles {ax..), the two parabasal bodies {par. h.), the 

 peristomal fiber {perist. f.) around the eytostome, the centrosome 

 {cent.), the rhizoplasts {rhiz.), blepharoplasts {bleph.) and the eight 

 flagella {fl.). 



