BRITISH SPONGE OF THE GENUS RAPHIODESMA. 99 



Furthermore, these fasciculi are stated to be carelessly thrown 

 together in every possible direction, the interstices forming 

 elongated, angular areas, like that of a confused mass of netting 

 extended in one direction only. Sufficient for our purpose this to 

 comprehend the character of the genus, so we will now go to the 

 special form within it, to which allusion has been made, and to 

 which I propose to combine H. macilenta. This is Eaphiodesma 

 sordida, described in the " Spongiadee," Vol. iii., p. 230. 



In this description, it, like H. macilenta, is parasitic — its colour 

 red or orange in the living state. Its skeleton spicules are sub- 

 clavate acuate, those of membranes the same, but more slender, a few 

 slender tricurvate ones. Retentive spicula contort bihamate 

 numerous, also bi-dentate, inequi-anchorate, dentato-palmate — the 

 latter congregated in rosette-shaped groups. 



Now this, as nearly as possible, accords with that of H. macilenta, 

 and what differences appear in Dr. Bowerbank's fuller account are 

 too slight to warrant any separation the one from the other. Solely 

 we miss the rosettes in the latter, which distinguish so many of 

 the genus Eaphiodesma, and are sometimes so abundantly found 

 in the species to which I consider it ought to be referred. But, 

 even this must give way, for in some of my preparations I have 

 detected this very interesting feature, and may also state that 

 it is often scarce in the species, wherein it is really a constant 

 form. I do not, therefore, think, that there can be the smallest 

 doubt, but that these described as two, are really but one species in 

 different stages of development.* And, if this be admitted, it is 

 necessary to point out, that the earlier condition of growth, seen in 

 the fascicules, do not show the peculiarity of being attached at the 

 centre, but rather are fixed at the base and spread out at the apices, 

 somewhat resembling the venerable scholastic institution called 

 *' birch." Nor in the full development of Eaphiodesma sordida is 

 this always lost, though in E. lingua, its near ally, the fasces strictly 

 conform to the tabulated characters of the genus. 



I have felt myself to be under a double necessity in thus intro- 

 ducing my subject, first, because the sponge I am about to describe 

 to you appeared to me, before I gave it an intimate examination, 

 to be that I have identified as //. macilenta, or, as rather the 

 early condition of E. sordida; secondly, because I cannot think 



* In this opinion onr member, Mr. Priest, to whom I am indebted for 

 several specimens of R. sordida, perfectly concurs, and was early to express 

 his decision. 



