80 
BowERBANK_, 071 GrauHa ciliata. 
process of nutrication in other beings. The latter observa- 
tions are published in the ^ Reports of the British Association' 
for 1856, p. 438, and for 1857, p. 121. 
In the cases of vital action in the Spongiadse, to which I 
have briefly alluded, the movements of the sponge have been 
of the simplest possible description, consisting only of the 
ciliary action and the contraction and dilatation of the mem- 
branous structures. But in another species of calcareous 
sponge, Grantia ciliata, in addition to these capabilities, we 
find a very much more intricate structure, and a complexity 
and extent of motion in its parts, which 1 have observed in 
no other sponge with which I am acquainted. In all the 
species of Grantia we find, to a greater or less extent, con- 
trivances for the protection of the sponge from the attacks 
of its enemies ; and in the great cloacal cavity of nearly all 
of them spicula are projected from the surface, slightly curving 
towards the mouth, in such a manner as efi'ectually to oppose 
the entrance of annelids or other predaceous creatures ; and 
the porous system is usually either overshadowed by groups 
of spicula, or covered by large spicula disposed in a longitu- 
dinal direction ; but in none of the other species of Grantia 
with which I am acquainted, have I ever observed the elabo- 
rate and beautiful modes of protection of the ineurrent and 
excurrent orifices that are apparent in the species I am about 
to describe, nor have I ever observed so great an amount of 
voluntary motion as exists in the organs of this sponge in 
any member of the Spongiadse. 
The species varies in size from two or three lines in length 
to upwards of two inches, and is usually of an elongate oval 
form, having a single cloaca extending from the base of the 
sponge to its apex, where the excurrent stream is discharged 
by a large orifice. 
In the living condition the surface of the sponge, when 
examined with a lens of two inches focus, appears to be com- 
pletely covered with minute conical papillae, from which a 
few slender, sharply pointed spicula are projected. When 
dried, these conical papillae appear as attenuated pencils of 
long spicula, and the whole sponge assumes a very hirsute 
appearance. The bundles of spicula are often seen in the 
dried specimens, reclining on the surface of the sponge in 
every imaginable direction. 
If we divide the sponge into equal parts through its long 
axis we readily obtain a view of the interstitial cells and their 
peculiar terminal apparatus. In the greater number of allied 
species they are of nearly the same diameter throughout 
their whole length, but in this sponge the distal extremity is 
