British Species of Sponges. 341 



{Halicliondria) farinaria, Bowk., Cliona celata, Hancock) and 

 are also to be found, thouc;li sparingly, in Tophon and Myxilla. 



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 Myxilla 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 Myxilla ? ruMginosa, 

 O. S. (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 Ilym. Dujardinii, Bowk., 

 from the English Channel, the long cylindrical spicules are 

 exceedingly numerous, wdiile 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 Dujardinii, 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 

 of Hymeniacidon Dujardinii, which it is in process of losing- 

 altogether. If so, it woidd be a degenerate form, the nearest 

 affinities of which would, I suppose, be difficult to determine. 

 Prof. Oscar Schmidt apparently places his Myxilla rubigi- 

 iiosa in the neighbourhood of Tedania and between that genus 

 and the Desmacidinse (Atlant. tSp.- Fauna, p. 44) — that is, in 

 very much the same position as appears to be occupied by 

 Trachytedania ? echinata. 



The foregoing pages testify passim to the obligations I am 

 under to Mr. H. J . Carter, F.li.S., for the liberal loan of speci- 



