254. Mr. H. J. Carter’s Contributions to our 
This tissue, when examined in water microscopically, is 
found to consist of short, soft, flaccid, apparently fusiform, 
opaque or translucent, whitish-yellow filaments of variable 
length, being in Chondrilla sacciformis (from the Mauritius) 
about 1-150th inch long and about 1-6000th inch thick in 
the middle: at least this is what may be inferred from the 
parts which project from a fringed-out edge of a fragment of 
the sponge just mentioned, when torn to pieces with needles, 
in water, and placed under a microscopic power of 300-400. 
diameters ; for it is not easy, as Schulze says, to isolate an 
entire filament. In the condition thus mentioned it may be 
observed to be translucent, and when unstranded to be made 
up of a number of almost immeasurable fibrils, like the finest 
hairs, which, although bound together in the poited end of 
the filament that may project from the border of the fragment 
into the water, sinks down on drying upon the glass slide into 
an expanded lash of fibrils that become elementarily undis- 
tinguishable in the gum-like homogeneous consistence which 
they altogether then assume. How far the filaments may be 
interunited like the elastic tissue of the warm-blooded animals, 
ex. gr. the human subject, I am unable to say ; but of course 
such an arrangement would enhance the elastic power of the 
tissue; and this interunion actually seems to be the case in 
a dyed and dried microscopic piece of Halisarca Dujardinit 
which I have mounted in balsam. At the same time, although 
generally distributed among the Spongida, the filaments of 
which this tissue is composed may not always present the 
same arrangement ; and, again, although often alluded to as 
being “ semicartilaginous,”’ it should be remembered that this 
refers to the consistence and not the structure, which is not 
that of cartilage. When exposed for some time to the dyeing 
influence of aniline (magenta-red ink) it only becomes faintly 
coloured, compared with the sponge-cells and other sarcodic 
particles with which it is intermixed ; while after having been 
dried and mounted in balsam im this state, no more of it can 
then be seen than has been above mentioned. As it is most 
abundant in those species of Carnosa which are most elastic 
and resilient, ev. gr. Chondrosia and Chondrilla, so it is least 
where the species is more easily torn to pieces, as in Halisarca 
Dujardinii, and apparently does not occur at all in Hl. lobularis, 
wherein, as before stated, | have not been able to discover any 
trace of it. How it originates | am unable to say ; but it seems 
to me not impossible that its filament may have been an elon- 
gated fusiform cell whose contents generally have become deve- 
loped into a bundle of fibrils such as that above deseribed ; 
nor am I able to say if it has any contractile power indepen- 
