var. spinispiculum, Ort. 161 
‘ anchoring-purposes, while those in the more exposed parts 
are more or less broken off. Such appears to be the case in 
Grantia ciliata, var. spinispiculum, 'Vhe capitate spiniferous 
or denticulated spicules (Pl. VIII. fig. 5) would appear to 
be particularly adapted for this purpose; but they are by no 
means so numerous as the pointed ones (fig. 4), neither are 
they a bit more confined to the root, while the capitate portion 
itself appears to arise from a modification of the end of the 
spiniferous portion of fig. 4, in which the substance of the 
latter becomes retracted into an inflation, which may be simply 
round (‘ Annals,’ 1876, vol. xvii. pl. xu. fig. 8), or provided 
with two or three recurved spines like that of the anchoring- 
spicule of Huplectella, as above stated. Hence I cannot agree 
with Schulze (Zeitschrift f. wiss. Zool. Bd. xxv. 3es Suppl. 
. 255) in deriving this from a quadriradiate spicule. 
The hardy nature of the Calcispongiz, which are so much 
more fragile and delicate in structure than the siliceous sponges, 
is very remarkable here, where the roof of the cavern in the 
New Red Sandstone rock at “ Straight Point” is just now 
absolutely covered with a mixture of all the species above 
mentioned, together with the siliceous species, viz. Halichon- 
dria panicea and H, sanguinea, Johnst., although it is only a 
few feet below high-water mark, and must be wholly uncovered 
by the sea for several hours twice a day, during which, of 
course, the sponges are kept wet by the dripping from the 
rock of the sea-water, which has also twice a day been ab- 
sorbed during the time that it has been under water. Thus, 
high-water mark is not less characterized by the well-known 
littoral siliceous species with linear, than calcareous sponges 
with triradiate spicules. 
I would here remark that to examine satisfactorily Grantia 
ciliata, var. spinispiculum, great delicacy of manipulation is 
required, otherwise most of the long spicules will inevitably 
be broken off, if they have not already suffered much in this 
way by the waves in their natural element. Thus it will be 
found advisable to bring away a.portion of the rock on which 
they are growing and place it in spirit then or afterwards, to 
examine this carefully under water at home, to raise the root 
with a spatuliform needle most carefully, and to transfer to a 
slide for microscopical examination or subsequent mounting in 
balsam (N.B. which does not show an acid reaction with test- 
paper) the parts that are required, by means of capillary attrac- 
tion, through a pipette. In this way the spiculation may be 
seen in situ; but when the entire spicules of different parts 
are required, then such portions of the body as might yield 
them are to be boiled separately, in liguor potasse, until they 
