BRITISH SPONGIAD.E. 279 



has not the slightest trace of the peculiar reticulated ap- 

 pearance of that species, when examined with a lens of two 

 inches focus. The specimens sent to me by Mr. Bean 

 were thoroughly washed, and in that state they were of a 

 light yellow colour, very fragile, readily compressible, and 

 soft to the touch. I subsequently received two small 

 specimens from Mr. Peach, which appeared to have been 

 dried in the state in which they came from the sea, and 

 these were of a nut-brown colour, well furnished with 

 sarcode, and were consequently considerably more rigid and 

 firm to the touch. The reticulations of the skeleton are 

 very distinct and regular ; they are rarely wider or longer 

 than the length of a single spiculum ; the primary lines of 

 the skeleton are most frequently unispicular, and the 

 secondary ones, I believe, always so. The skeleton spicula 

 are regularly acerate, and are short and stout in their pro- 

 portions. A full-sized one measured r^th inch long. The 

 dermal membrane in all the specimens I have examined 

 was in so dilapidated a condition as scarcely to allow of my 

 speaking with certainty on the subject of the specific cha- 

 racters to be derived from it. On the board to which four 

 specimens are attached, in the Johnstonian collection in 

 the British Museum, and which are designated Halichon- 

 dria ciuerea, there are two on one piece of card ; the 

 smaller one is identical with our /. permollis. The mark 

 on the card is 17 c . 



4. Isodictya simulo, Bowerbank. 



Sponge. Coating. Surface smooth, or rarely minutely 

 hispid. Oscula simple, dispersed, large. Pores incon- 

 spicuous. Dermal membrane pellucid, spiculous ; 

 spicula acerate, slender, dispersed ; shorter than those 

 of the skeleton, moderately abundant. Skeleton : 

 primary lines bi- or trispiculous ; secondary lines uni- 

 spiculous ; spicula sub-fusiformi acerate, short, and 

 rather stout. Interstitial membranes, tension spicula, 

 same as those of the dermal membrane ; few in num- 



