190 LIEBERKUHN, ON MOTILE 
been described as assuming a stellate figure, the stellate ones 
in turn becoming globular, but also this without any loco- 
motion. This phenomenon occurs, not only in the cells of 
the uninjured substance, but also in those which have been 
detached. But locomotion has not as yet been described, and 
it is to this point that the following observations relate. 
In all specimens of Spongille, whether developed from ova 
or from gemmules, or from separated portions, the most 
varied arrangement of the parenchymatous tissues may be 
seen, whilst the siliceous skeleton in the different species 
retains the same characteristic form. When the external 
membrane is quite transparent, we may observe, in many 
instances, a cavernous structure, consisting of more or less 
completely closed cavities, of irregular form, and of which the 
superficial ones are bounded by the external membrane, and 
admit the water which flows in through the inhalent orifices. 
Occasionally, however, they are not furnished with these 
external orifices, but have others communicating with the 
exhalent canals. Instead of these cavities, wider canals 
may also be seen, ramifying over a large portion of the 
sponge, and which open directly into the exhalent passages ; 
in this way a considerable extent of the external membranes 
may be unfurnished with inhalent orifices. In other cases, 
however, these orifices exist over almost the entire surface 
of the sponge, and usually lead directly into a large cayity 
belonging to the inhalent system. The irregular septa, by 
which these cavities are bounded, contain in their walls the 
ciliary apparatus. All these cavities, whether belonging to 
the in- or exhalent system, may be traversed by parenchy- 
matous trabecule of the most various thickness, and similar 
trabecule may sometimes even be seen crossing the exha- 
lent canals. These trabecule are sometimes very closely 
approximated, and, at the same time, are so broad and thin, 
that an observer might suppose that he was looking at a 
portion of the outer membrane with inhalent orifices. 
In other instances no membraniform septa of this kind 
are to be seen; but, instead of them, nearly the whole body 
is pervaded by slenderer or thicker trabeculez, which are con- 
nected at numerous points with the external membrane, 
and are continued beneath it to great lengths. They exhibit 
a great variety of aspect; sometimes no indication whatever 
of a cellular structure is apparent in them, and they appear 
to be bounded by a smooth, transparent fine contour, whilst 
in the interior may be seen numerous strongly refracting 
granules, more or less closely crowded together. In. the 
finest of these filaments, even when viewed by a stronger 
