Monthly Microscopical) —- Royal Microscopical Socrety. 251 
sponges belonging to it are structurally composed of anastomosing 
silicious fibres. This feature is evident in Huplectella, Aphrocallistes, 
Dactylocalyx, &e., but is not applicable to such species as Hyalo- 
nema and Pheronema, or the recently described Askonema, Sym- 
pagella, and Lanuginella, 
Dr. Wyville Thomson has proposed to distinguish all these 
forms, taken together, by the name of the Virrea ; but the diagnosis 
he gives is wanting in correctness, and his order must necessarily 
make room for a more carefully drawn up and more trustworthy 
one. One of the primary distinctions of his Virrea is,* “ that all the 
spicules of these sponges, without exception, whether of the skele- 
ton or of the sarcode, are referable to the hexradiate type.” Such 
is by no means the case, and is, in short, entirely out of harmony 
with existing facts. This is fully shown in the simple hair-like 
spicula forming the greater portion of the skeleton of Askonema, in 
the long anchoring forms and the short fusiform ones of Pheronema, 
and in the various attenuate varieties peculiar to Aulodictyon Wood- 
wardi and fecunda. Indeed, it is difficult to select any species 
in which the diagnosis laid down by Dr. Thomson holds good. If 
the forms just summarized are referable to the hexradiate type, so 
are the simple acerate ones of Spongilla, and the term VirrEa may 
be applied with an equal amount of justice to every other group 
of the silicious sponges; but it being clearly evident that no such 
division as the one proposed by Dr. Thomson really exists, we are 
necessarily driven to seek further for a more carefully and correctly 
characterized diagnosis. 
Dr. Oscar Schmidt, in his fine memoir already quoted, proposes 
to distinguish the whole series under the title of the Hexacrinet- 
Lips, from the fact of all the species sharing in common the pos- 
session of hexradiate spicula; though, at the same time, he does 
not commit himself, like Dr. Thomson, to the assertion that every 
spiculum is referable to that hexradiate type. This as a primary 
order or division is so natural, and the name is so fully suggestive 
of the common character by which Dr. Oscar Schmidt proposes to 
distinguish the group, that I shall not hesitate henceforth to adopt 
it, and most naturalists will, I think, recognize its importance and 
appropriateness. 
Subordinate to this primary order, Dr. J. E. Gray’s division of 
the CoraLiiosponai#, including all those sponge forms with a 
coalescing or reticulate silicious skeleton, remains intact ; while of 
equal value to this I propose to form a new sub-order, which I 
distinguish as the Catiicisponcim, to include all such cup- or sac- 
shaped forms as Hyalonema, Pheronema, and Askonema, and which, 
while possessing the hexradiate silicious spicula characteristic of the 
* See ‘Philosophical Transactions’ for 1869, and ‘Annals and Mag. Nat. 
Hist.’ 
