Mr. H. J. Carter on Spongilla. 365 
with the cilia waving zn it.” By the “last occasion” is 
meant that in which the young Spongilla was grown from the 
statoblast in a watch-glass, as usual, for microscopical exami- 
nation, which is the only convenient way of examining it, as 
then a perfect sponge is obtained which can be brought under 
a higher power without molestation (and eventually torn to 
pieces if necessary) during the whole course of its development. 
Detaching a portion from a large mass does not offer all 
these advantages, from the shock to the living functions oc- 
easioned by such a procedure; while to obtain the young 
Spongille it is only necessary to get a portion of an old kiving 
specimen bearing statoblasts, and, having taken out a few (six 
to twelve) of the latter, to roll them gently between the folds of 
a towel to free them from all extra material as much as pos- 
sible, place them in a watch-glass so as not to touch each 
other, with a little water, in a saucer or dish filled with small 
shot, to keep the saucer upright, and, covering them with a 
glass shade, transfer the whole to a window-bench opposite 
the light. In a few days the young Spongilla may be ob- 
served (from its white colour) issuing from the statoblast and 
gluing the latter as well as itself to the watch-glass, when it 
will be ready for transfer to the field of the microscope for 
examination, care being taken that it is never uncovered by 
the water, which may be replenished as often as necessary ; 
but of course the object-glass (when + inch with high ocular 
is used for viewing the minuter structure) must admit of being 
dipped into the water without suffusion of the lens. 
Returning to the ‘‘ Spermaballen,” it is even now difficult 
to recognize them in the living or dead state, on account of 
their being so much like the ampullaceous sacs (Geiselkammer) 
on the one hand and ova of the same size on the other. Their 
being unconnected with the branches of the canal-system may 
help to distinguish them from the ampullaceous sacs, which in 
diameter are much of the same size, viz. ‘0:05 millim.” 
(Schulze), m addition to their minute granular contents, 
which are the heads of the young spermatozoa; but this 
again confounds them with the ova at an early stage of the 
latter. When the spermatozoa are fully developed within 
their capsule at the time of examination, of course they may 
be easily recognized; but this coincidence does not happen 
often. Even in one of Prof. Schulze’s exquisite preparations 
which he kindly sent me, of the “‘ Spermabailen” in Halisarca 
lobularis, I can only see one with the cilia inside it, while the 
rest 1 should not recognize if not told by the label on the slide 
what they are ; hence, by the inexperienced thus unassisted, the 
“ Spermaballen ” may be often seen without being recognized. 
