244 Records of the Indian Museum. [VoL. V, 
part reaches to within a short distance of the aperture; the 
epithelium is columnar, the cells are in a single layer, and the 
lining has a ragged appearance, due to the fact that the inner 
portions of the cells are not in contact with each other; these 
cells are mucous cells, their bodies being for the most part clear 
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FIG. 2.—Part of a transverse section passing through the male aperture. 
The character of the epithelium lining the last part of the atrium, the flattening 
of the nerve cord in this region, its ‘ Neurochordréhrchen ’, the great bulk of the 
chloragogen cells, and the Sporozoa in the alimentary tract (the nucleus of one 
individual has broken up), are illustrated. The ventral vessel is the structure 
just dorsal to the nerve cord. 
Zeiss’s drawing apparatus, obj. DD, oc. 6. 
Altr., atrium: c., circular muscular layer ; ch/., chloragogen cells; d.v., dorsal 
vessel; ep., surface epithelium; gg., nerve ganglion cells; znt., intestine; /., longi- 
tudinal muscular layer; sp., sporozoa in intestine; v.n.c., ventral nerve cord; &. 
male aperture. 
and non-staining, and masses of a clear secretion are cast out into 
the lumen; the walls of the tube are thinner than those of the 
first part, and its outline is far less regular,—not only internally, 
owing to the ragged nature of the lining, but externally also, 
since a number of small diverticula are given off from it; these 
diverticula are lined by a similar epithelium to that of the tube 
