Knowledge of the Spongida. 311 
meter, but is sufficiently large for me to see that, in general 
character, it is, as above stated, precisely like Ectyon sparsus. 
I have used a masculine termination for the specific name, in 
accordance with that adopted by Dr. Gray (Proc. Zool. Soc. 
Lond. 1867, p. 515), otherwise the termination on” indi- 
cated neutrality; but as “Hctyon”’ appears to have no other 
meaning than that which Dr. Gray has assigned to it, and, 
like many other names applied to his genera of sponges, also 
appears to be nothing more than a “ fortuitous combination of 
letters,” as he himself states (op. e¢ loc. cit. p. 500), I follow 
his example. Moreover, as there can be no doubt that the 
generic name was intended for Dr. Bowerbank’s “ West- 
Indian sponge” (Mon. Brit. Spong. vol. i. p. 275, pl. 
xvii. fig. 289), otherwise undescribed, I have used the term 
“ Ketyon sparsus” (Nos. 462-3, being in halves) for that 
species in the British Museum which, if not identical with, 
is, at all events, most closely allied to it (‘ Annals,’ 7. c.) ; hence 
am carrying on Dr. Gray’s appellative. 
Ectyon flabelliformis, n. sp. (Pl. XI. fig. 1, 1a.) 
Flabelliform, pedunculate, composed of a large thin frond 
divided into three lobes, one central and two lateral, presenting 
* concentric lines or ridges of growth on the surface; round 
undulating margin and short peduncular stem. Consistence 
tough, firm. Colour brown-yellow. Vents circular, large, 
numerous, and alone on one side, more or less irregular in 
form, and accompanied by smaller ones in groups, as in Hetyon 
sparsus (see Pl. XII. fig. 2, c), on the other, where the latter 
appear to be for the pores, and the most regular or circular 
ones only of the former for the vents, all sphinctrally tym- 
panized by the dermal sarcode. Structure compact, clathrous 
throughout, the clathrous cavities extending to. the surtace, 
where they are also tympanized by the dermal sarcode, whose 
disappearance in the dried state causes some confusion as to 
function from their resemblance to the great irregularly cir- 
cumscribed vents just mentioned (see Pl. XII. fig. 2, d). 
Spicule of one form only, viz. acuate, curved chiefly to- 
wards the large end, pointed at the other, bearing verticils of 
short spines throughout at nearly equal distances from each 
other ; pomt smooth, large and spined (PI. XI. fig. 1, a) ; 
average largest size of spicule about 30 by 3-6000ths inch in its 
year, returned it, saying that he had not time to describe the speci- 
mens, and finally from Dr. Dickie to myself in July 1872. I have 
described several of them, but the rest are too fragmentary and rotten 
from the presence of sea-salt to be now worth any thing. 
