176 BULLETIN OF THE 
animal This vibratile plate is homologous with the vibratile combs, of which 
it is the exact continuance. The bright crimson pigment spots found in a row 
at its base and along the auricles are probably functional, but, whether sensory 
or not, has not been determined. 
From the origin of the tentacle to the angle formed by the oral lappets and 
a ridge from the auricular appendages, Plate VIII. fig. 10, there passes a row of 
small tentacula-like bodies, which closely resemble the filaments or secondary 
They resemble closely the tentacles 
appendages to the rudimentary tentacle. 
Folds in the walls 
foung along the bell margin in Aurelia (Plate VII. fig. 6). 
of the intestine near the upper end of its course are well marked, These struc- 
tures are figured in Bolina by Mr. Agassiz. 
part of the funnel and the otocyst of M. Leidyt is figured in Plate 
iglion beneath the 
Their course 
The upper 
VIII. fig. 6. The bundles of nerves which pass from the gar 
otocyst distribute nerves to all the important organs of the body. 
can be traced very well, even to the margin of the oral lappets. They are un- 
branched, and of a white, almost silvery color. Their course in a small portion 
of the inner surface of the oral lappets has the appearance shown in Plate VIII. 
fig. 11. "There is in the adult no circumscribed aborally placed sense organ of 
dumb-bell shape similar to what has been mentioned in the young, Plate VILI. 
fig. 5. A part of the body walls around the otocyst has a granulated appear- 
ance, which may represent this structure in a reduced form. 
The otocyst is a two-layered sac containing otoliths arranged in a cluster. 
This sac is without apical opening. The connection of the otoliths with the 
ganglion is through the walls of the floor upon which the cluster rests, and not 
by suspension from the upper walls of the capsule. Four bundles of nerves 
arise in a symmetrical manner from the ganglion, two of which are well 
marked, and extend into the oral lappets, d, Fig. 6. 
The network of lines on the inner walls and surface of the oral lappets is 
arranged with great regularity, and does not form those characteristic spots, four 
in number, which exist in Ocyroé maculata, Rang. Each line in the network is 
made up of small cells, laid side by side. Nerve fibres are especially rich in 
the oral lappets, which, as a result, are highly sensitive, quickly responding by 
retraction when the surface is touched. 
CAMBRIDGE, February, 1881. 
