88 



THE PROTOZOA 



form two or more grains when there are numerous flagella. Thus, 

 in Lophomonas, which shows the extreme of complication, there are 

 numerous basal granules corresponding to the tuft of flagella 

 (Fig. 45). Each basal granule in this case is divided into a proximal 



FIG. 44. Diagrammatic representation of the possible phylogenetic origin of the 

 different types of flagellar attachment in flagellates. For the sake of sim- 

 plicity it is supposed that the animal has but a single flagellum. O, Non- 

 flagelJated cell with a centriole in the nucleus ; O b , in a cell like the last a 

 flagellum arises from the centriole ; l a , condition with a flagellum arising 

 close beside the nucleus ; l b , condition with the blepharoplast quite separate 

 from the nucleus ; 2 a , division of the single centriole into a definitive centro- 

 some and a blepharoplast, which becomes quite independent (2 b ) of the 

 nucleus ; 3 a , division of both nucleus and centriole to form distinct kinetic 

 and trophic nuclei, each with its own centriole ; 3 h , the kinetonuclear centriole 

 remains within the nucleus ; 3 C , the kinetonuclear centriole becomes distinct 

 from the nucleus ; 3 d , condition with a single centriole in the cell ; 3 e , condition 

 with a blepharoplast distinct from the centrioles of the^two nuclei. 



and a distal granule, and the pairs of granules are arranged in a 

 ring, interrupted at one point ; the tuft of flagella takes origin from 

 the distal granules of the ring. When the nucleus divides, the 

 daughter-centrosomes give rise to new rings of blepharoplasts, 



