52 JAMES FRANCIS ABBOTT, 
In the roof of this pharyngeal cavity is the opening of a vertical 
canal which leads up to the infundibulum and which with the 
pharynx itself comprises the stomodaeum. This canal is strongly 
compressed in the stomachal plane. Distally it opens into the cup- 
shaped infundibulum, which lies just beneath the otolith capsule 
From the infundibulum four main canals arise, two in the sagittal 
(stomachal) and two in the transverse (tentacular) plane. The latter 
pair run to the muscular base of the pinnate tentacles, penetrate 
them and also spread out in a sort of anastomosing network enclosing 
the sheath. Lateral branches are sent out that ramify to the 
periphery, anastomosing and subdividing until they end in blind 
finger-shaped terminations. The other two main branches of the 
canal system arising in the sagittal plane, sometimes at a trifle 
lower level than those in the tentacular plane, subdivide into two 
canals. In some specimens this subdivision occurs so close to the 
infundibulum as to give the appearance of two independent canals, 
arising on either side. In most specimens however the parent stem 
is evident. The two secondary canals arising from its subdivision, 
run close to the dorsal surface of the body and are the ones which 
send out the processes described above as respiratory tentacles. As 
already indicated, the course of the canals is bent toward the 
tentacular plane so that the two pairs on either side assume roughly 
the form of a figure “8”. - From these main canals smaller subdivisions 
arise all along the course which are continued downwards and 
laterally, anastomosing and uniting with those arising from the canals 
in the tentacular plane. In ©. willeyi the peripheral digestive tracts 
partake more of the nature of sinuses, divided off from one another 
by trabeculae or partitions of connective tissue which extend from 
the dorsal body wall to the ventral. These trabeculae are 
especially evident near the periphery, but towards the center the 
lacunae take on the normal character of thin walled tubes. The 
“sinuses”, then, are really greatly enlarged divisions of the canal 
system where the upper and lower walls have become confluent with 
the dorsal and ventral body walls and where the sides of two 
adjacent tubules have come together and fused. In many instances 
the fusion is Incomplete and the limits of the individual walls may 
be made out. In ©. mitsukurü, these conditions do not appear to 
be developed or at least only in a limited region about midway 
from infundibulum to periphery. In this species the amount of 
parenchyma is very much greater than in ©. willeyi and the digestive 
