MUSEUM OF COMPARATIVE ZOOLOGY. 167 
the dip-net, in the month of May. I have given a figure, Plate VIT. fig. 9, of an 
octant of this immature Cyanea seen from the oral side. This octant, as the 
other seven which compose the disk, bears an otocyst, and hence I shall in my 
description designate it as the sense octant. The lappets, one or 
the radius in which the otocyst lies, are called in my description 
pets, or lappets of the sense organs. 
The movements of the umbrella of the ephyra are very rapid, and when av 
rest its lobes are thrown backward and upward, as in Plate VII. fig. 4*, expand- 
ing the oral folds and causing them to projeet in the manner shown in that 
figure. The diameter is between an eighth and a quarter of an inch. It has a 
light brown color, and at a superficial glance resembles an ephyra of Aurelia. 
The likeness of the ephyra of Cyanea to that of Pelagia cyanella as figured by 
Prof. Agassiz, or of Chrysaora as represented by Claus, is so close, that it might 
easily be mistaken for that of either of these genera. 
There are eight sense lobes in the ephyra, as in the adult Cyanea. The in- 
cisions in the margin separating the lobes are very deep, and so wide that these 
bodies are removed. from each other by an interval equal to the width of the 
lobe itself. The whole aboral surface of the disk is covered with very minute 
papillæ, which a little later in the growth of the ephyra elongate into promi- 
nent filaments, of which I shall speak later. To anticipate, let me say that 
the developed filaments are figured in Plate VII. fig. 1. The whole disk of the 
ephyra, especially the margin of the disk, has very thin walls. 
The structure of the “lower floor” of the umbrella in the ephyra is very 
complicated. In the centre of the disk on this side there is found a mouth, 
which is a simple opening surrounded by a slightly raised, quadrate-shaped 
ridge, forming the lips. The elevation of this ridge above the lower floor of 
the ephyra is very slight, and the lips are as yet without folds. There are, 
however, four re-entering angles, one on each side of the rectangular ridge, 
which impart to the mouth as seen from below a cross-shaped outline. Plate 
VII. figs. 9, 10. The points of this cruciform figure later elongate, and, hang- 
ing down like curtains, form the complicated folds of the oral appendages to the 
mouth. 
From the under surface of the “lower floor” of the ephyra in the interval 
left by the re-entering angles in the ridge about the mouth there is formed a 
tentacle (S), differing in no respect from the first tentacles found on the 
umbrella margin, As there are four of these re-entering angles about the 
mouth, there are at first only four of these tentacles, one for each angle. Each 
one originates as a simple bud, and as they become more developed smaller 
buds form near and upon the base of that first developed. Plate VII. fig. 9". 
The position in which this tentacle is found refers it to the sexual organs. In 
the adult Cyanea these tentacles are very numerous, and are found in rows 
above the sexual glands. In my figure, Plate VIT. fig. 13, the natural position 
has been reversed, and the row of sexual filaments is found below the ovaries. 
In the genus Cyanea the sexual filaments of the adult are very minute ; in 
Polybostricha dubia, Br. they reach a much greater development. 
