MUSEUM OF COMPARATIVE ZOOLOGY. 81 
above, in having eight otocysts and the same number of rudimentary tentacles 
alternating with them on the bell margin. The marginal lappets, instead of 
being long and pointed, as in the above Ephyra, are rounded, and almost oval 
in contour. The tentacles are very short, resembling little buds in the interval 
alternating between the marginal bell lappets. 
The youngest Ephyra of Linerges which was taken is much younger than any 
yet figured. The umbrella has a disk-like form, is flat, and has a coloration 
similar to that of the adult. It was not traced into a larva like that which is 
elsewhere* doubtfully described as the young of L. Mercurius. 
Agalma Okenii Escu. 
_ Several specimens of A. Okenii t were collected in Castle Harbor. This 
species has never before been taken on this side of the Atlantic. A. Okenw 
resembles our common Agalma, A. elegans F., but is easily distinguished from 
it by the rigid character of the body and the thickness and peculiar form of the 
covering-scales. 
The axis in larger specimens is about three inches long, and has little flexi- 
bility. The polyp stem, or that part of the axis which bears the polypites and 
their covering-scales, is almost straight, and on account of the thickness and 
close approximation of the covering-scales is never thrown into those curves 
which impart so much grace to the Agalma when in motion. The color of the 
axis is yellow and orange. . The float and axis resemble in most of their exter- 
nal features the same structures in Agalma. The swimming-bells are similar 
to those of A. papillosum F. in possessing blind extensions of the bell cavity 
into the gelatinous horns which arise on either side of the attachment to the 
axis and embrace the stem. 
The covering-scales are very thick, and stand out at right angles to the stem 
at their points of attachment. In looking at the Physophore from the side, it 
was not successful in my search for it. Casstopea has sixteen sense-bodies, and in 
that respect differs very widely from most Discophora. In one or two other gen- 
era, as Collaspis and Atolla, there are more than eight marginal sense-bodies, but the 
differences between these genera and the Ephyra mentioned seem too great for a 
reference of it to them. 
If my Ephyra is in reality the young of Cassiopea, or some other genus with like 
sedentary habits, it furnishes us with the interesting fact, which I have long sus- 
pected, that in its younger larve Cassiopea is free-swimming, and has embryonic 
tentacles in the Ephyra which are lost in the adult. 
* Bull. Mus. Comp. Zodl., Vol. IX. No. 7. 
t This species of Agalma closely resembles Crystallodes rigidum Haeck., with 
which it is probably identical. It seems also to be the same as a Siphonophore 
described by Gegenbaur, from the South Atlantic, lat. 2° S., long. 26° W. (Neue 
Beitrage zur naheren Kenntniss der Siphonophoren). I have followed the latter 
author in considering it the same as the Agalma Okenii described by Eschscholtz, 
from the North Pacific Ocean. 
