462 WILLIAM NICOLL. 
are large, rounded, oval cells, measuring ‘045 by ‘03 mm. 
They present a distinct cell wall, loosely granular contents 
and a small, dense nucleus, measuring ‘006 mm, ‘The nucleus 
stains dark red and the cell contents hght purple with 
hemalum-eosin. Jacoby’s opinion of these cells is highly 
improbable. In reality they appear to be true cutaneous 
glands. Their marked resemblance both in shape and 
staining properties to the true subcutaneous glands, which 
in this species occur not only in front of, but also behind 
the ventral sucker, cannot be ignored. This, together with 
their distinctly marginal situation, if not a positive proof of 
their glandular nature, is at least strong evidence in favour 
of such a supposition, In addition it should be noted that 
these cells are smaller and less numerous in the oral sucker 
and are entirely absent from the pharynx. 
The third variety of cell really consists of at least three 
different kinds. he first of these (fig. 14, p z) is confined 
to the outer zone, i.e. immediately beneath the outer mem- 
brane of the sucker. ‘Their nuclei are small, dense, round 
bodies, measuring ‘008 mm. ‘The nucleoli are small and 
inconspicuous. ‘The cell-body is usually fairly definite and of 
eranular structure. The second kind (fig. 14, Mm z) occupies 
the median zone with the myoblasts. Their nuclei are 
invariably oval, and measure ‘0115 by ‘008 mm. ‘They stain 
lightly and their chromatin granules are arranged peri- 
pherally. The nucleoli are always distinct. No trace of 
cell-body, however, can be detected with ordinary staining 
methods. The third kind (fig. 14, 1 z) les in the inner 
zone. They are distinctly multipolar, and in a tangential 
section their fibrils can be seen anastomosing with each 
other. The cell-body takes on a deeper hue than any of the 
other cells, almost purple. They measure ‘02 to ‘(03 mm., 
and their nuclei, which are small, dense and usually oval, 
measure ‘007 by ‘006 mm. 
As to the function of these last three kinds of cells any 
expression of opinion would be hazardous. Many authors 
have advanced theories as to their nature, but without any 
