EUPLECTELLA. 
241 
were not first spun and then interwoven, but were formed as 
interwoven, the two processes going on simultaneously, or pari 
passu ; but as in the cancellous texture of bone, the plates of 
bone are not first formed and then fitted to one another, as in 
building a house of cards, but the forming and the fitting go 
on together in the course of the molecular growth, I pre- 
sume also that in the beautiful object which we call the 
Euplectella we have but the skeleton, and that in the living 
state the exquisite structure of the flinty framework may be 
veiled by the delicate gelatinous enveloping organic tissue.” — 
Lin. Trans, xiii. 121. 
This common jelly not only developes the beautiful cornu- 
copia-shaped vase, but if an accident occurs to it the rent is 
darned in a most workmanlike manner, as may be observed in 
a specimen which is in Mrs. Gray’s collection. 
The skeleton above described, is interspersed with abundance 
of stellate spicules of very varying forms which are not attached 
to the skeleton itself, but belong to the layer of thin flesh or 
sarcode with which it is covered when in a living state. These 
spicules are of three distinct forms, and they all have acute tips 
to their rays; the first form is the most variable, generally 
varying from a simple fusiform spicule to a well made six rayed 
one, and sometimes these rays are divided into divergent 
branches. A series of these forms is figured in Bowerb. Brit. 
Sponges , t. 7, f. 174-187, and the more branched t. 8, f. 188- 
189, f. 5, 6. The second kind has only four rays, each of which are 
divided at the top into several short diverging rays like claws, 
figured also in Bowerb. B. Sponges , t. 8, f. 195, f. 8. The 
third kind has also only four rays but these soon divide into a 
number of elongated rays which converge together at the top 
and form a bell-shaped body, f. 7. See Bowerb. B. Sponges , t. 8, 
f. 193-194. 
Somewhat similar many-rayed stellate spicules have been 
observed occupying a similar situation in the beautiful coral- 
like siliceous sponge from Barbadoes, called Dactylocalyx 
Panicea , of which there are two or three beautiful specimens 
in the British Museum. But the spicules of this sponge differ 
from all the forms observed in Euplectella in having the top of 
each of the rays furnished with a small knob like the head of a 
common pin ; they are also figured in Bowerbank? s B. Sponges , 
t. 8, f. 190-192. 
The filaments forming the fibres are very long, slender, 
nearly of the same diameter through their whole length, and 
most of them have a smooth surface. They are solid, elastic, 
and less brittle than one would expect from their hardness, but 
this arises from their peculiar composition and external structure. 
