BRITISH SPONGIAD^l. 373 



line in thickness ; the surface was even, but no oscula were 

 visible. The other was about three quarters of an inch 

 long, and nearly the same in breadth. The surface was 

 uneven, rising in irregular ridges or tubercular masses to 

 about the height of two lines from the base. There were 

 four oscula on the most elevated parts of the sponge ; they 

 were from half to three fourths of a line in diameter. Some 

 of the large areas of the dermal membrane were aspiculous ; 

 in others, there were a few scattered tension spicula. The 

 thickest of the two specimens was much more rigid in its 

 structure than those previously described. 



In a small specimen in the living condition, which I sub- 

 sequently obtained at Hastings, the fibres were, some of 

 them, thickly coated with sarcode, and others entirely enve- 

 loped in it, so that the interstices of the skeleton were 

 completely filled with it. An abundance of nutrient mole- 

 cules were attached to the surface of the sarcode, and others 

 were apparently buried beneath the surface. The colour 

 of the sarcode was precisely the same as that of the skeleton 

 fibres. 



6. Chalina li mb at a, Bowerbank. 



Spongia limbata, Montagu. 

 Johnston. 



Sponge. Massive, sessile, subglobular, lobecl, or coating. 

 Surface hispid. Oscula simple, large, few in number. 

 Pores inconspicuous. Dermis irregularly and diffusely 

 fibro-reticulate ; fibres multispiculous ; spicula, fusi- 

 formi-acerate, slender ; dermal membrane pellucid, 

 abundantly spiculous ; spicula same as those of the 

 fibre. Skeleton, compact and regular; primary and 

 secondary lines multispiculous, spicula, fusiformi- 

 acerate, slender. Interstitial membranes, nearly 

 obsolete, abundantly spiculous ; spicula same as those 

 of the skeleton. 



