235 



RAPHIODESMA, Bowerbank. 



In the course of the re-examination of the species of 

 my genus Hymeniacidon for illustration in the present 

 volume I was struck by the discrepancies in the struc- 

 ture of the skeleton of the species that I had designated 

 in vol. ii, page 187, Hymeniacidon lingua, as compared 

 with the skeletons of the other species of that genus. 

 I had also the advantage of the examination of a series 

 of specimens of the species under consideration in a fine 

 state of preservation, that I had received from my 

 friend Mr. Peach, and from which I felt convinced of 

 the necessity of establishing a separate genus for the 

 reception of sponges having the fasciculated skeleton 

 structure of the one I had designated H. lingua, 

 and I was the more strongly confirmed in this idea 

 by the acquirement of a second species, Raphiodesma 

 sordida, in which the skeleton structures are in 

 perfect accordance with those of the species I had 

 designated Hymeniacidon lingua. 



I propose, therefore, the following characters as 

 those of the new genus. 



RAPHIODESMA, Bowerbank. 

 Plate XL VII, fig. 8. 



Skeleton. Without fibre, composed of an irregular 

 network of polyspiculous faggot-like bundles ; the 

 spicula of which are compactly cemented together at 

 the middle, but are radiating at their terminations. 



The structure of the skeleton in this genus is very 

 remarkable. It is composed of numerous fasciculi of 

 spicula like elongated faggots, the central portions being 

 compactly cemented together, while both terminations 

 present a loosely radiating appearance. The mode of 



