OSCULA AND ANATOMY OF LEUCOSOLENIA CLATHRUS. 483 
13,a and 6. In the middle of each drawing is seen one of the 
amceboid wandering cells, one and the same cell both in 13 a 
and 13 6. Now 138 a@ is drawn with the microscope at the 
lower focus, and shows the fusiform cells ; while 13 6 is drawn 
at the upper focus, and shows the other kind of cells. 12a 
represents one of the second kind of cells macerated out from 
the same preparation from which fig. 12 was drawn. I take it 
that the fusiform cells are more specially differentiated ecto- 
derm-cells, while the other kind are more ordinary ectoderm- 
cells. In transverse sections of the sphincter the cells on one 
surface commonly appear more rounded and project higher 
than on the other (figs. 7 a, 8). I believe that the rounded 
projecting cells are the fusiform cells of the flat preparations, 
and the flat cells the others. It is difficult to be certain of 
this point; 1 infer it from the fact that in such sections the 
rounded cells are closer together than the flat ones. The two 
kinds of cell appear to occur indifferently on one or the other 
side of the sphincter. From the left side of fig. 7 a, it would 
appear as if both sides of the sphincter might, in places, be 
formed only of fusiform cells. 
The nuclei of the cells composing the sphincter have a 
similar structure in both kinds of cells. They are spherical 
or slightly ovate, measuring in glycerine preparations about 
6°5 uw, in Canada balsam preparations (prepared in all points 
in the same manner as the glycerine ones) about 5:2 yn. The 
nucleus rarely has one distinct nucleolus; more usually 
several small ones. In preparations hardened with Her- 
mann’s fluid, and stained by Flemming’s method! with saf- 
franin, gentian violet, and orange G., the structure of the 
nucleus is well shown, especially if the sections are cut very 
thin (4 or 5 «). Then the whole nucleus is seen to be filled 
with a fine network, which may be thickened at several nodal 
points, sometimes greatly at one, producing the appearance of 
a nucleolus. Without entering at present into further histo- 
1 Vide his paper in the ‘ Arch. f. mikr. Anat.,’ vol. xxxvii (1891), ‘‘ Ueber 
Theilung und Kernformen bei Leukocyten, und iiber deren Attractions- 
spharen,” p. 296. 
