104 Vniversitij of California Publications in Zoology [Vol. 20 



complex. They arise from its basal lobes as branches which break 

 up into the minute, threadlike oblique fibers. These follow an oblique 

 course posteriorly, continually giving off branches, part of which go 

 to the basal granules of the flagella and the remainder cross and 

 intercross in an irregular anastomosing network through the ectoplasm 

 of the body (fig. A, ob. /.). Near the distal limits of the ectoplasmic 

 zone these fibers fade out and disappear. 



In their structure they are homogenous and not granular, and 

 their width is about equal to that of the flagella. The smaller branches 

 leading out to the basal granules are more slender. At the anterior 

 end, near the basal lobes of the centroblepharoplast, they take a darker 

 stain than is the case farther posteriorly, though this may be largely 

 due to their slightlj^ greater thickness in the posterior region. 



Centroblepharoplast: The oblique fibers are intimately related 

 to the centroblepharoplast. This organelle in Leidyopsis differs but 

 little if any from that of Trichonympha. It forms a tubular or rod- 

 shaped structure in the pointed anterior end of the body (fig. A, 

 centrobleph.: pi. 1.3, figs. 1, 3), from the"ba.se of which stream out the 

 oblique fibers. 



The tubular part of the centroblepharoplast is composed of a 

 number of rods or strands which extend to the base of the cuplike 

 depression at the anterior end of the cone-shaped portion of the 

 body. Here the ends are joined together by a circular band of darkly 

 staining material, the center of which is occupied by the core of endo- 

 plasm (pi. 13, figs. 2, 10, 13). The tube extends posteriorly to near 

 the base of the cone where it expands into a collar-like structure com- 

 posed of several large, irregular lobes, which may sometimes be united 

 into a solid band encircling the base of the tube (pi. 13, fig. 3). 

 Distally these lobes fray out into the oblique fibers. 



The center of the tube is occupied by a slender core of endoplasm 

 continuous with the endoplasm of the bodJ^ This extends up to the 

 base of the small, cup-shaped depression, where it may be seen as a 

 light area within a dark ring (pi. 13, fig. 10). 



The tubular part of the centroblepharoplast complex may present 

 some modifications, such as the formation of short, spinelike processes 

 extending out from the tip (fig. 3) or along its sides (fig. 1). At the 

 time of division the cuplike depression and operculum disappear, 

 leaving the tip of the centroblepharoplast complex exposed at the 

 surface. The entire structure takes a deep stain with iron haema- 

 toxylin, making it a conspicuous part of the body in stained prepara- 

 tions. 



