222 University of California Publications in Zoology [Vol. 19 



with safranin, the periphery appears to contain masses of granules 

 of chromatin while the center is homogeneous and more or less trans- 

 lucent. Surrounding this karyosome is a hyaline area, measuring 

 from 1 to 3/x in width, which is always transparent and takes none 

 of the nucleus stains but is lightly colored with eosin and acid fuchsia 

 about the same as the cytoplasm. Around this there is a peripheral 

 area, varying in width and definiteness, in which irregular chromatin 

 masses, small, variable in size, number and shape, occur. This area 

 is from y 2 to 3^, in width. It is surrounded by the nuclear membrane. 



The chromatin material is frequently encrusted upon the nuclear 

 membrane in the resting stages of the nucleus. Much chromatin is 

 accumulated in masses scattered peripherally between the hyaline 

 area and the membrane, at times (presumably when anabolic processes 

 greatly predominate over the katabolic) reducing the hyaline area 

 to a minimum. But the largest amount of the chromatin is found in 

 the karyosome which stains deeply with all nuclear stains. Thus the 

 chromatin encrusted upon the membrane, that occurring in the peri- 

 pheral zone, and that making up the karyosome, or the larger part 

 of it, all has to be accounted for later in mitosis. 



The blepharoplast, located at the anterior end, is irregular in size 

 and shape. It consists of a mass of chromatoidal protoplasm which 

 tends to become stellate in shape, much like a nerve cell, deeply 

 staining strands extending out into the cytoplasm between the 

 vacuoles (pi. 9, fig. 20). Embedded in this blepharoplast are two 

 basal granules, which are distinctly red when stained with safranin. 

 gentian-violet, orange G, and acid fuchsin. From each of these 

 basal granules two equal flagella arise. From the blepharoplast. 

 probably from each of the basal granules, arise the two rhizoplast s, 

 which extend as strands from the chromatoidal mass, but instead of 

 remaining upon the surface as the other strands do, run interiorly 

 to the nucleus, enlarging at the nuclear membrane into a minute 

 granule. In some instances the nuclear membrane is drawn up at 

 the point of attachment of the extranuclear rhizoplast. In several 

 instances (pi. 7, fig. 1), an intranuclear rhizoplast seems to penetrate 

 the membrane and run to the central karyosome. 



The cytoplasm immediately surrounding the nucleus is closely 

 appressed to the membrane, making it difficult at times to distinguish 

 the latter. It is denser and more granular, and extends out into tin- 

 body in strands which lie between the protoplasmic vacuoles. It 

 stains much as the peripheral nuclear area with iron haematoxylin. 



