92 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
very thin structureless basement membrane, or simply on 
an obscurely differentiated part of the ordinary 
mesenchymal tissue. Fig. 3, Pl. II, represents a very 
usual condition, in which the cells are rounded and lie 
closely together, but not at all arranged in the manner 
characteristic of a true epithelium; the height of these 
cells measured from the basement membrane 1s 0'014 mm. 
Sometimes they are more separated from each other than 
the figure indicates, being still roughly globular in form. 
Sometimes they are columnar, and are arranged in a 
manner very similar to that seen in some Triclad 
Turbellaria;* and cells of this kind are represented in 
figs. 4and 5. They are elongated at right angles to the 
length of the intestine, or they may le along the surface 
of the latter. The smaller rounded or globular cells are 
probably such as are not actively engaged in the absorp- 
tion of food matter, and their protoplasm is denser than 
in the more elongated cells. The latter are generally 
club-shapea, the rounded, globular ends projecting freely 
into the lumen of the intestine. Sometimes they present 
knob-hke protuberances on their sides, and suggest that 
they may execute amoeboid movements for the purpose 
of taking up food particles. The extreme of this form of 
cell is represented in fig. 4, where the proximal part of 
the cell is seen to be drawn out to form a long pedicel, 
constricted in two places, and terminating distally in a 
club-shaped enlargement; the length of this cell is 
007 mm. In these columnar, or club-like cells, the 
terminal parts usually stain lightly, as 1f they were 
occupied with large vacuoles containing non-staining 
matter. In all types the nucleus, which is of the usual 
form, is situated at the base of the cell, and the proto- 
*See Schneider, Lehrbuch Vergleichenden Histologie, Jena, 1902; 
Fig. 321, p. 304. 
