EEVISION ''BRITISH SPONGIADiE." 255 



include such greatly differing forms as Hymeraphia 

 vermiculata, B. and H. verticillata, B. (which I refer 

 to Axinella and Hymeraphia respectively), I have 

 not thought it advisable, to make use of that genus. 

 Plocamia coriacea, B., LXXVI. (Eidley and Dendy, 

 14, p. 158; Topsent, 18, p. 117.) 



Family III. Axinellid^, Eidley and Dendy. 

 Skeleton typically consisting of ascending axes of fibres 

 from which arise subsidiary fibres radiating to the surface, 

 but may be reticulate. Megascleres chiefly monactinals 

 to which diactinals may be added. Microscleres rarely 

 present ; if present, raphides, microxea, cladostrongyla or 

 asters. 



Genus Hymeniacidon, Bowerbank. 

 Sponge massive. Skeleton reticulate. Megascleres 

 monactinal. No microscleres. 



Note. In regard to /iJ. gelatinosum see Halisarca. 

 Hymeniacidon aldousii, B., XCII. 



„ aureum, Mont., XXXIV. 



,, callosum, B., 4, IV. 



,, carunculum, B., XXXII. (Kidley and 



Dendy, 14, p. 167.) 

 ,, consimile, B., XXXIII. 



fallax, B., XXXIII. 

 ? ,, gelatinosum, B., XXXVIII. 



,, hillieri, B., 4, III. 



,, invalidum, B., LXXXV. 



? ,, involutum, B., 4, X. 



,, mammeatum, B., XXXIII. 



,, medium, B., LXXXV. 



,, nodosum, B., 4, XII. 



,, pacliydeimum, B., XXXIV. 



„ perleve, Mont., XXXIV. 



