36 
servable in the membrane of the ball. The base also by 
which it was attached to the Spirula shell (apparently only 
very loosely) showed nothing particularly remarkable. The 
consistence of the membrane, as far as it could be ascertained 
from the pressure of the overlying-glass, was that of a tole- 
rably tough and very elastic jelly, somewhat comparable to 
that of the umbrella of the firmer Medusae ; for instance, 
those of Trachynema and Rhizostoma. Like the latter, this 
membrane showed itself very indifferent to reagents ; it 
was not coloured by the application of carmine, nor by 
iodine and sidphuric acid. After long remaining in iodine 
it became of a pale yellow. Acetic acid did not much alter 
it, nor did any of the mineral acids. In caustic potash 
it swelled up and dissolved slowly. 
The orange-red contents of the balls appeared in unin- 
jured specimens within the closed, globular membrane, as 
a thoroughly homogeneous, consistent, obscurely granulated 
mass, in which might be observed very numerous, exceed- 
ingly fine particles, and a small quantity of strongly refract- 
ing red grains. On moderate compression with the stage- 
glass, the balls allowed themselves to be pretty strongly 
compressed spheroidally, and took the shape of a double 
convex lens of 0‘3 mm. diameter. On relaxation of the 
pressure, they expanded again to their former globular form. 
The opaque centre of the balls became under pressure more 
transparent, without, however, exhibiting any structure. 
My first impression that the balls were eggs already ap- 
peared to me wholly improbable, as there was no appearance 
of a germ-cell (nucleus) throughout the homogeneous con- 
tents. It was soon entirely set aside by the different stages 
of development exhibited by several of the balls, as well 
as by the behaviour of the contents when pressed out of 
the halls. 
While in most of the balls the contents lay everywhere 
thickly on the inside of the membrane, and entirely filled 
the interior of the whole membranous envelope, in some in- 
dividuals the contents were a little retracted and apparently 
thickened ; and a space filled with a clear fluid interposed 
between the membrane and the thickened contents (fig. 2). 
In some balls the edge of the central thickened orange-red 
mass was a perfectly defined and regular boundary line. In 
others, on the contrary, it appeared to be regularly indented. 
There were about twenty indentations to be seen on the 
edge of the red ball. On examination of the surface it 
ajipeared that these indentations were the indication of a 
regular series of convex eminences on the entire surface of 
