214 
LlEBERKiiHN, ON SPONGILL^E. 
colour. In the lowermost layers of the living sponge, con- 
tiguous to the dead portions, there occasionally occur large 
quantities of glittering white gemmules, but, except in 
colour, otherwise like the brown ones, and containing, like 
them, spherical bodies, composed of larger and smaller fat- 
like granules and an albuminous substance. These bodies 
are about the size of the largest sponge-cells, and are readily 
broken up by pressure. Others, again, may be seen with a 
very delicate case, though furnished with very transparent 
amphidiscs, and in these gemmules the contained spherical 
bodies are less readily broken up. When a portion of sponge 
containing gemmules of this kind is torn asunder with a 
fine needle under water, some whitish, ill-defined, spherical 
portions, of about the same dimensions as the gemmules, will 
be noticed. They present the following characters : 
They are constituted of two distinct substances, one 
external, having a low refractive power, something like the 
common sponge- cells, and an interior spherical mass, with 
strong refractive power, almost like collections of fatty 
particles. When one of these bodies is crushed, it breaks 
up into ceUseform structures of two kinds, and Ijoth about 
the same size as the sponge-cells. Those of which the inte- 
rior highly refracting part of the corpuscles was composed, 
cohere together, and are constituted of a motile sarcode 
substance. The outer layer appears to be composed of 
firmly agglutinated cellseform globules, some very closely 
resembling the sponge- cells in the disposition of the nucleus 
and nucleolus, whilst others inclosed amphidiscs. Some of 
the amphidiscs thus contained in the cells were perfect in 
form, and others obviously only in process of formation. 
The amphidisc-cells did not present any nucleus, but were 
very distinctly defined. 
Occasionally Lieberkiihn noticed among the white gem- 
mules, some which, together with free amphidiscs, supported 
on their transparent investing membrane others contained 
in vesicles or cells. From what he observed, he con- 
cludes that the above- described bodies represent immature 
gemmules. He is unacquainted with similar phenomena in 
the case of the smooth gemmules, remarking only that up to 
the present time he has never noticed, in one and the same 
portion of sponge, gemmules with amphidiscs together with 
smooth ones at the same time, although both forms occur at 
all seasons. 
The usual contents of the gemmules have been described 
by Meyen (Miiller^s 'Archiv,^ 1839, p. 83) . In many instances 
Lieberkiihn found that the globular arrangement no longer 
