The Morphology of Coeloplana. 61 
in a sort of spreading brush or fan, the apex directed against the 
otolith at four equidistant points, an arrangement that recalls the 
four S shaped supports in the Cydippida. In the center of the ciliated 
zone (i. e. directly below the otolith) and also in a second zone 
above it the cells forming the wall of the cup are not ciliated but 
glandular. The nuclei are very large and deeply staining and the 
cells are usually crowded with small granules. 
Just outside the otolith capsule in the angles formed by the 
“intersecting tentacular and sagittal planes are four large nerve 
ganglia (cf. KOROTNEFF) that send off fibers to form a sort of diffuse 
peripheral system, and on the other hand supply fibers that surround 
the lower part of the capsule as an enveloping sheath. Each ganglion 
is directly opposite the point of insertion of the supporting cilia on 
the otolith. The cells of the nerve tracts and ganglia are large, 
with large nuclei, and stain intensely in methyl blue. 
In addition to the central sense organ the yellow pigment spots 
on the periphery probably have a sensory function tho I have been 
unable to work out any details regarding them. 
e) Parenchyma and musculature. 
In conformity with its life habits Coeloplana has a much 
firmer body consistency than purely pelagic forms. The spaces 
between the gastric canals the tentacle sheaths and the epi- 
dermis are small and filled with a parenchymatous tissue well 
calculated to withstand the various strains to which the body is 
subjected. From the basement membrane of the epidermis fine 
branching muscle processes enter the parenchyma and ramify through- 
out its extent. The cell elements are of various sorts, — 1) delicate 
much branched cells with dendritic processes; 2) long usually wavy 
and thickened muscle cells with terminal branches only, which stain 
intensely with methyl blue; 3) oval or irregular cells with large 
nucleus, which may be early stages in development of the elongate 
muscle cells. 
There is another variety of cell of doubtful nature to be found 
scattered through the parenchyma. These are very long and thick, 
irregular in shape and resemble a crumpled up sausage. The cyto- 
plasm is granular in some, alveolar in others. No nucleus was 
demonstrable. They may possibly be parasitic in nature. 
