1869.] DR. J. S. BOWERBANK ON SILICEO-FIBROUS SPONGES. 83 
by the acid imbedded together in their natural conditions in the 
membranes of the animal, this at once removes all doubts respecting 
their really appertaining to the animal under consideration. 
In a small fragment of the skeleton from the inner surface of the 
sponge near the base I found portions of the interstitial membranes 
filling the areas of the network of the skeleton in a good state of 
preservation ; they were coated with dense yellow sarcode, in which 
were a considerable number of trifurcated hexradiate stellate spicula 
completely imbedded; but I could not detect any of the minute 
attenuato-stellate, the equiangular triradiate, or the small acerate 
spicula; it may therefore be fairly inferred, from their absence in the 
interstitial membranes, that the latter three forms appertain more 
especially to the dermal one, in which they occur in such abundance. 
In the Museum of the Jardin des Plantes at Paris there are two 
very interesting specimens of Dactylocalyx pumiceus; one is a 
small and apparently young specimen, the other a tall ewer-shaped 
specimen in a well-developed adult condition. The first of these 
two specimens, I was informed, had not been in the possession of 
Dr. Lacaze-Duthiers more than a few weeks previously to my seeing 
it. It was labelled “Iphiteon panicea, Valenciennes. La Marti- 
nique.’ It is 2? inches in height, and the same in diameter at the 
top of the cup. It is based on the edge of a flat piece of what is 
apparently tufa. In form, it isa symmetrical cup without a pe- 
dicel ; the base is about 14 inch by | inch in diameter. The thick- 
ness of the cup at the margin varies from a quarter to rather exceed- 
ing half an inch. Onthe outer surface there are deep channels run- 
ning most frequently in a longitudinal direction, varying in width 
from about 1 to 2 lines, and in length from 3 inch to 2 inches; and 
where they are not present, their places are supplied by round or 
oval deep apertures. On the interior surface there are also 9 or 10 
lines of large round or oval apertures radiating from the base of the 
cup to the margin. Many of these deep interstitial cavities pass 
entirely through the sides of the cup, so that they are common to 
both internal and external surfaces. In some of these cavities on 
the inside of the cup there were one or two long slender spicula, the 
whole lengths of which could not be seen. 
The structural peculiarities of the skeleton agree perfectly with 
those of the type specimen of Stutchbury’s genus Daciylecalyx, and 
the specific characters, as far as they were present, with the species 
pumiceus. The specimen has been too well washed, to make it look 
beautiful; but notwithstanding this injudicious treatment, I found, 
in the minute section of the skeleton, made at right angles to its sur- 
face, several little groups of spinulo-trifurcated hexradiate spicula 
imbedded in the remains of the animal matter. 
The second or ewer-shaped specimen is 14 inches in height ; its 
upper margin is not circular, but has one portion of its cireumfe- 
rence bent outward and downward like the lip of a large water-ewer. 
At this depressed part it is 12? inches across; and at right angles to 
this line the measurement is 10 inches. It is labelled ‘ Zphiteon 
panicea”’ from “ Martinique par M. Plée 1829.” It has no part 
