The Somatic Nuclei of Certain Cestodes. 
155 
geneous in character, and usually lack 'the granules which are typically 
present in the densely stained cells of adult Cestodes. Tliey vary in size, 
sliape and staining density. Surro unding these nuclei there mav be a 
few delicate Strands of protoplasm forming tlie cell body. Evidence of 
nuclear membranes, reticula or »nucleoli« is usually lacking 1 ). More- 
over the absence of nuclear structure is not due to density of stain, for 
in cells which are lighter stained these structures are still lacking. Fur- 
thermore mere differences in size (thickness), state of contraction of the 
tissue, or eccentric action of the stain, will not account for differences 
in staining density of different cells; because two closely adjacent cells 
may show a differenca in staining density, and the same may be true of 
two cells of the same thickness as shown by careful measurement. 
Scattered tliru the sub-cuticida are numerous masses similar in 
staining character to the larger nuclei, but which are much smaller, vary- 
ing also in size and shape. Tliese differ apparently in no wav save in 
size from the larger, more definite nuclei, and are I believe small, irre- 
gularly distributed masses of nuclear matter. 
Here practically the entire cell is composed of nuclear matter elab- 
orated under conditions probably nutritive and developmental, which 
are not as yet understood, as I have prevjousiy maintained for Cysti- 
cercus pisiformis (1. c., p. 241). 
2000 nuclei examined 2 ) showed no evidence of mitosis 3 ). 
Sp. (from Cynoscion regalis). 
(Figs. 15 and 16.) 
Conditions here are similar to those described for the preceding 
form. In many cases the entire cell body is densely stained, containing, 
as I believe, diffuse nuclear matter. In some, however, a few deeper 
staining granules may be seen and in a few cases a more or less definite 
nucleus. Nearly adjacent cells varv in density of stain. In one section I 
find a group of protoplasmic masses, presenting the following conditions. 
Two of them show an indefinite darkly-stained granulär structure, and 
probably contain nuclear matter diffused thruout the cell body. In a 
third is a Collection of definite granules, surrounding a peripheral ring 
H In some cases I find a slight Suggestion of a membrane, and in one case a fairly 
definite membrane is present. I have also seen one case of a »nucleolus« in a sub- 
cuticular cell. 
2 ) See footnote 1), p. 145. 
3 ) The tissue, however, was probably not actively growing. 
