British Species of Sponges. 341 
(Halichondria) farinaria, Bowk., Cliona celata, Hancock) and 
are also to be found, though sparingly, in Jophon and Myzilla, 
On the whole it seems best, notwithstanding these discrep- 
ancies, to refer this sponge provisionally to Trachytedania ; 
the only alternatives, apparently, would be either to create a 
new genus for its reception or to consider it an abnormal 
form of Myzxilla or Lophon: there is not, I think, sufficient 
warrant for the first course, and for the last it would be 
necessary to assume the loss of two forms of microsclera. 
Mr. Carter has pointed out to me the general resemblance 
of this sponge to, and the partial correspondence of its spicu- 
lation with that of, Hymeniacidon Dujardinii, Bowk., which 
latter he is disposed to identify with Mywilla? rubiginosa, 
O. 8. (Sp. des Adriat. Meer. p. 72), of which again M. oliva- 
cea, O. S. (op. cit. pp. 11 and 83) is in all probability only 
another name. In specimens of Hym. Dwardinii, Bowk., 
from the English Channel, the long cylindrical spicules are 
exceedingly numerous, while the only other kind of spicule, 
the spined style, is rare. That the latter nevertheless 
represents the main skeletal spicules and the former those of 
the dermal skeleton seems probable from their respective 
positions in the sponge-substance, as well as from their forms. 
This view seems to receive confirmation from a preparation of 
a sponge of this species which Mr. Carter has kindly lent me, 
labelled “Hymeniacidon Duyardinii, Bk., ovigerous, Vigo 
Bay.” It contains dark yellow circular bodies, which Mr. 
Carter informs me are embryos, still in the substance of the 
sponge. ‘The embryos contain numerous spicules, but of one 
form only, namely, entirely spined styles similar in character 
to those of the sponge, but not above one quarter of their 
length and breadth. In the rest of the sponge the tylota are 
as numerous and the styles as rare as in the British specimens 
above mentioned. ‘The fact seems worth recording; I do not 
know whether the inference may be drawn from it that the 
styles are the oldest, and theretore the main skeletal spicules 
ot Hymeniacidon Dujardinii, which it is in process of losing 
altogether. If so, it would be a degenerate form, the nearest 
affinities of which would, I suppose, be difficult to determine. 
Prof. Oscar Schmidt apparently places his Myzxilla rubigi- 
nosa in the neighbourhood of Yedania and between that genus 
and the Desmacidine (Atlant. Sp. Fauna, p. 44)—that is, in 
very much the same position as appears to be occupied by 
Lrachytedania? echinata. 
The foregoing pages testify passim to the obligations I am 
under to Mr. H. J. Carter, F'.R.S., for the liberal loan of speci- 
