226 A MONOGRAPH OF THE 



congeners; and, with English naturaUsts of that period, it 

 would have been arranged among the species of Halichon- 

 dria, and on the subsequent division of the latter, it naturally 

 takes its place as a Hymeniacidon. Well founded genera 

 should always be maintained if possible, but I do not see 

 the necessity for scrupulously maintaining those which are 

 so only in name, and are not so in essential character. 



39. Hymeniacidon Bucklandi, Bowerbank. 



Sponge. Massive, sessile ; surface minutely hispid, 

 even. Oscula simple, dispersed. Pores inconspicuous. 

 Dermis stout, minutely maculated ; furnished abun- 

 dantly with minute, entirely spined, cylindrical spicula ; 

 spines large, and obtusely terminated. Skeleton spi- 

 cula; spiculated triradiate and attenuato-biangulated, 

 large and stout. Tension spicula tricurvate, few in 

 number. Sarcode ; dark purple, semi-opaque, abound- 

 ing with minute, entirely spined, cylindrical spicula, 

 like those of the dermis. 



Colour. — Alive, external dark purple ; internal, light 

 brown. 



Habitat. — Torquay, Dr. Battersby ; Guernsey, Mrs. 

 Buckland. 



This remarkable sponge, in its dried state, very closely 

 resembles in firmness and colour a piece of dried boiled 

 bullock's liver. A specimen with which I have been 

 favoured by the late Mrs. Buckland, who obtained it at 

 Guernsey, at the extreme low- water mark, was two inches 

 in length, and one in breadth and thickness. When a thin 

 slice from the surface is mounted in Canada balsam, the 

 dermis is seen to abound in small, ill-defined dark maculae, 

 and minute, entirely spined, cylindrical spicula. If the 

 section be mounted for examination in water, the first of 

 these characters is but indistinctly visible, while the spicula 

 are completely invisible, in consequence of the density and 



