172 BULLETIN OF THE 
alone stretches over the terminal end of this organ. In this layer are epi- 
thelian cells, modified into nervous elements. The otocyst is fastened to the 
‘style, which bears it on the lower side, so that, instead of being continued 
directly into it, the cavity opens from the upper sides of the otocyst through 
the under side of the style. 
Exceptions to the regular number of otocysts in Cyanea and Aurelia are 
common. 
Aurelia flavidula Pur. € Les. 
A. few specimens of this medusa were taken each summer. They were as a 
general thing fewer in number and smaller than those found in Massachusetts 
Bay. An Aurelia as large as à water-bucket, which is not a rare sight north of 
Cape Cod, I have not seen in the southern bays. A side view of a small Aure- 
lia is beautifully figured in the well-known “ Contributions to the Natural 
History of the United States.” The figure is taken from a medusa with con- 
tracted bell, and oral lobes, and consequently there is no representation in 16 
of the otocysts. I have given a figure of Aurelia, with disk expanded and oral 
appendages extended, in order to show, more plainly than one in which these 
parts are drawn together can, the position of the sense organs to which I 
wish to call special attention. (Plate VII. fig. 2.) 
The otocysts of Aurelia differ very greatly from those of Cyanea, yet still we 
can in both recognize homologous parts. The oral curtains hanging down 
one oneach side of the otocyst of Cyanea are wanting as such in Aurelia. They 
are represented in part by two lappets, one on each side of the sense bulb, a, 
Plate VII. fig. 3. Corresponding morphologically with the dendritic divisions 
found in the oral curtains and adjoining sense lobes of Cyanea, there are in 
Aurelia, arising as branches from the prolongation of the stomach into the 
sense octant, two blindly ending horn-shaped tubes, which, as seen from above 
(Plate VIT. fig. 3, b), appear to embrace the style of the otocyst, and extend a 
short distance into the base of the lappets, a, Plate VII. fig. 3. The prolonga- 
tion of the stomach into the sense octant, in Aurela, takes the form of a 
straight tube, the diameter of which is quite small. This tube, after arising 
from the stomach, passes directly towards the margin of the disk, and when 
near the otocyst opens into a circular-shaped enlargement. Into the same 
cavity pass also two other pairs of chymiferous tubes, one on. each side, which 
are branches from another system of vessels likewise extensions of the stomach. 
From the under floor of this cavity, which is shown in Plate VII. fig. 3*, near 
its peripheral part, there arise three small-vessels besides those which have 
been already mentioned. One of these, the median, is continued directly into 
the cavity of the otocyst, passing through the style of the same, while the others, 
the two lateral branches, are the horn-shaped tubes which seem to embrace the 
style of the otocyst, and enter for a short distance the lappets of the sense bulb. 
Their extremities never become dendritic, but end blindly in the substance of 
the lappet. As has been hinted at above, these sense lappets in Aurelia are 
represented in part by the oral curtains hanging down, one on each side of the 
