Knowledge of the Spongida. 313 
orifice. Here, of course, as in all hollow sponges, the vents 
open on the inner surface of the cylinder, and therefore few or 
none are on the outside, which thus contrasts strongly with 
that of the solid forms. 
On the other hand there is a solid cylindrical form in the 
Liverpool Free Museum, of which Mr. T. Higgin has also 
caused a photograph to be made, and from which the illustra- 
tion in Pl. XIi. (fig. 2) has been lithographed. It is 164 
inches high by 43 inches thick in its greatest dimensions, and 
therefore upwards of three times as large as the photograph, 
but clearly shows on the surface the scattered vents (fig. 2, 
b) and cribriform grouping of the “smaller holes’? between 
them (fig. 2, c), to which I have already alluded, but which I 
have heretofore not had an opportunity of illustrating in an 
entire specimen of this species; hence am here again indebted 
to Mr. ‘Thos. Higgin for his kind assistance *. Being club- 
shaped as well as cylindrical, I have, for distinction’s sake, 
called this variety of Ectyon sparsus “ claveeformis” (Pl. XII. 
fig. 2). Internally the colour is brown-yellow, but, probably 
from exposure on the beach where the specimen may have 
been picked up, the surface had become so bleached and 
white as to simulate a vetreous sponge ; now, however, this has 
changed to dirty grey after exposure to a smoky atmosphere. 
It is registered 28. 3. 78. 5. As I have lately seen several 
examples of this form, but less club-shaped and more regu- 
larly cylindrical, I am inclined to think that it is the kind of 
growth most commonly assumed by the specimens of this 
species which come from the West Indies generally; while 
one cannot help being impressed with the fact that the spicules 
of all the forms from this district are so much alike that 
they alone present no specific difference. 
For such sponges Dr. Bowerbank in 1866 (Mon. B. 8S. 
vol, ii. p. 14) instituted his genus “ Ophlitaspongia,” having 
first illustrated them in 1862 (Phil. Trans. pl. xxx. fig. 7). 
After this Duchassaing de Fonbressin and G. Michelotti de- 
scribed four species from the Caribbean Sea under the generic 
name ‘“‘Agelas” (‘ Spongiaires de la Mer Caraibe,’ p. 76, 
1864), apparently illustrating the two above mentioned, viz. 
Ketyon sparsus and E. flabelliformis (pl. xv. figs. 1 and 2, 
together with their characteristic spiculation in the diagram 
“G,” pl. i.) ; but, as usual, there is too much room left for 
doubt in their descriptions to make them available. Subse- 
* Mr. Higgin got these photographs made for illustrating a description 
of the Ectyonida which had been commenced by himself; but not knowing 
when he might have time to complete it, they were handed over to me 
for this purpose. 
