litis] Kofoid and Christ iatiscn: On Giardia niuris (Grassi) 35 



neuromotor apparatus of these organisms. This apparatus is cou- 

 tinuous as one structure throughout, and consists of the two blepharo- 

 plasts (bleph.) from which radiate the two rhizoplasts (rhiz.), the 

 anterior or lateral {lat. fl.), postero-lateral (post. lat. fl.) and the free 

 ventral {fr. vent, fl.) flagella. and the axostyle (ax.) terminating 

 posteriorly in the posterior flagella {post, fl., fig. A). 



The blepharoplasts are two large, deeply staining, spheroidal bodies 

 symmetrically placed at the right and left sides of the anterior end 

 of the axostyle. They are joined by a slender, deeply staining trans- 

 verse fiber or commissure, which cannot be the homologue of the 

 paradesmose joining blepharoplasts in binary fission of trichomonad 

 flagellates (Kofoid and Swezy, 1915 a. b) for this joins eentrosomes 

 when they emerge from the blepharoplasts in Trichomonas, and does 

 not unite them here. Three flagella and one-half of the axostyle, 

 terminating in one posterior flagellum take their origin or radiate 

 from each blepharoplast and each is connected with one nucleus. 



This neuromotor system is also joined to the parabasal bodies, that 

 is, to the pair of large, subellipsoidal, deeply staining masses sometimes 

 fused into one, lying dorsal to the middle of the axostyle. The con- 

 necting fibers (pi. 5, fig. 5; pi. 8, figs. 53, 56) to the parabasals are 

 made out with great difficulty and have been found by us only in 

 several favorably located individuals. They join the dorsal side of 

 the axostyle and we are not able to follow them separately to the 

 blepharoplasts, nor to be certain of their constant or general occur- 

 rence because of the great technical difficulty of detecting such small 

 structures in the mass of stained material above or below them in all 

 except lateral views. 



These bodies have been regarded l)y previous investigators prior to 

 Alexeieff (1914) as "ratselhafte Korper" of unknown significance and 

 morphological relationship. We believe, because of their staiuability, 

 connection with the neuromotor apparatus (blepharoplast?), and 

 because of the evident relationship of Giardia to the trichomonads, 

 that this body is homologous with the parabasal of Devescovina of 

 Janicki (1911) and with the chromatic basal rod or parabasal (see 

 Kofoid and Swezy, 1915 a, b) of Trichomonas. This homology was 

 first tentatively suggested by Alexeieff (1914). 



The flagella are eight in number, all trail posteriorly, and emerge 

 on the ventral side in four bilaterally placed pairs, the antero-laterals 

 (ant. lat. fl., fig. A), postero-laterals {post. lat. fl.), free ventrals {fr. 



