200 
NOTES AND MEMORANDA. 
intestine pass onwards through the action of the very thin muscular 
coat of this portion of the digestive tube, and probably also under 
that of the muscular columns. This mass divides and becomes sur- 
rounded with a thin envelope secreted by the epithelimn of the intestine. 
The result is the production of solid excrements, which collect in the 
stercoral pouch. A chalky liquid secreted by the malpighian vessels 
also collects there, and exhibits innumerable corpuscles, extremely 
small, discoid, or spherical, grouped in pairs, and sometimes accom- 
])anied with microscopic crystals in rhomboidal tables. The secretion 
of these tubes is neutral and contains salts, amongst which is chloride 
of sodium. So far as can be judged, it does not contain uric acid, or 
urates, but it is easy to show the presence of guanine. The stercoral 
pouch is a reservoir collecting the residues of digestion, and the 
malpighian products. Its contents are expelled at considerably long 
intervals under the influence of its well-developed muscular coat. 
We must remember, finally, that the dipneumonous spiders can live 
for many months, that is to say, during the whole season of physio- 
logical activity, without food. 
Hooked Spines on the “ Boot-fibres ” of British Polyzoa . — In No. 72 
(Zoology) of the ‘ Journal of the Linnean Society’ Mr. C. W. Peach, 
A.L.S., writes in regard to Scrupocellaria scruposa, that although it is 
common and well known he is able to add a little to its history. 
Having received a specimen on a sponge (Halichondria panicea) from 
the Frith of Forth, and desiring to know how it moored itself to the 
soft body, he cut open the sponge, and found, as he thought, curious 
sponge-spicules, differing from all he had previously seen. On tearing 
it from the sponge, he saw that the “ spicules ” were actually the 
“tubulous root-fibres” of the Scrupocellaria. Having hitherto con- 
sidered these “root-fibres” as smooth, with a disk for adhesion to 
anything, at the lowest end, it was a new fact to find that they were 
armed with stout hooked spines where they were buried in the sponge, 
the points of the hooks bent towards the zoophyte, like the flukes of 
an anchor pointing towards the bow of a ship when the cable is 
stretched tight. These hooked spines are shaped like the thorn of a 
rose tree, and surround the “ root-fibres ” in a rather irregular manner, 
and when dragged out of the sponge hold in their grasp numbers of 
the sponge-spicules ; this at once explained why these “ root-fibres ” 
were armed with hooks, and the points bent towards the zoophyte. 
In another specimen from the same locality it was found that the 
spines, &c., were constant under similar circumstances. A specimen 
of Canda reptans, collected in Cornwall before 1849, on examination, 
showed similar hooked spines on the “ root-fibres.” In the hope of 
confirming this with a Scotch specimen, Canda reptans was got from 
Newhaven (N.B.), unfortunately not on a sponge, but on Flustra 
foliacea ; here the hooks were absent ; but the tips of the “ root- 
fibres ” were furnished with short radiating processes spread out at 
right angles, and from these short disk-like processes were inserted 
into the openings and body of the cells of the Flustra, thus giving a 
firm grip on this larger fan-shaped and firmer sui)port, and enabling 
the zoophyte to ride safely in a storm. 
