The Morphology of Coeloplana. 59 
other species and apparently no diagonal fibers. The staining 
reactions are peculiar. Using Mawnn’s Eosin-Wasserblau method 
followed by Orange G, the five cords of longitudinal fibers stain 
intense red, — the circular sheath about the central one, blue, — 
the outer layer, yellow. and the adhesive cells themselves purple. 
The primary tentacle is made up of a thick bundle of 
longitudinal muscles immeshed in connective tissue and surrounding 
a core of the same substance, — a structure very much resembling 
a telegraph cable. Each muscle strand seems to be developed from 
a single cell by an enormous elongation of the cell body and con- 
tains many nuclei. The inner wall of the tentacular sheath is 
lined in part with an endothelial lining like that of the gastric 
canals. This is supported by a network of connective tissue and 
muscle cells. Elsewhere the epithelium is cubical and _ heavily 
flagellate. 
A peculiar condition is observable in some preparations of 
C. mitsukuru. The lining cells bud off as they do in the gastric 
canals, and appear to take up phagocytic functions. At least in 
areas where a rapid proliferation is taking place the cavity of the 
sheath contains great numbers of similar cells that have ingested 
fragments of colloblasts or frequently whole cells, — spiral and all 
(Fig. 23). There seems to be no reason for doubting that these 
phagocytes arise from the inner epithelium of the sheath. 
d) The otolith. 
The otolith with its accessory structures does not appear to 
differ from the general Ctenophore type. The otolith itself consists 
of a number of calcareous granules held in an organic matrix and 
swung in a cup by means of cilia. The whole apparatus is usually 
sunk some distance below the surface when Coeloplana is contracted 
and the overlapping edges of the epithelium appear like fieshy lips. 
The cup is subglobular in shape and closed over above by a mem- 
brane formed by the fusion of cilia springing from cells in the 
cupwall. The cells whose cilia support the otolith lie in a zone 
about the lower half of the cup. The cilia are long and arise from 
the columnar cells of the ciliated zone in densely staining knots of 
protoplasm as previously described for the cilia in other parts of 
the body. The cilia form a complete circle about the otolith without 
appearing to fuse with each other. However, instead of being 
attached to the otolith evenly on all sides they are gathered together 
