BRITISH SPONGIADiE. ' 311 



25. IsoDlcTYA PALM ATA, Boioetbank. 



HXTJCHOlfDaiA BALSATA, JOhnston. 



Sponge. Sessile or slightly pedicelled, arborescent or pal- 

 mate and digitate^ compressed. Surface even. Os- 

 cnla simple, or margins slightly elevated. Pores in- 

 * conspieuous. Dermal membrane pellucid, spiculous ; 

 tension spicula same as those of the skeleton, irregu- 

 larly dispersed, few in number ; and equi-anchorate 

 retentive spicula with bifurcate terminations, with ex- 

 flected points; irregularly dispersed, very numerous. 

 Skeleton. Open and diffuse ; primary and secondary 

 lines multispiculous,. rete more than the length of one 

 spiculum in width ; spicula acerate, stout, and rather 

 short. Interstitial membranes. Tension spicula same 

 as those of the skeleton j retentive spicula same as 

 in the dermal membrane, irregularly dispersed, ex- 

 ceedingly numerous. 



Colour. ^-ly^ak red brown in the dried state, or light 

 gray. 



HahitaL — Coasts- of Northumberland and Scotland, Mr. 

 Alder and Mr. Peach. Orkney Islands, Mr. McAndrew. 



E!isamined.-^liLrt the dried state. 



This sponge is, I believe, the Mermaid's; glove of the 

 Cfekney fishermen. I received a fine specimen from Mr. 

 McAndrew in 1851. It is thirteen inches in heighti and 

 about nine inches at its greatest width ; it is palmate, and 

 has a rude resemblance to a glove. This is the only case 

 in which I have seen it assume this form. It usually con- 

 sis)ts of a number of stout, iwegular,, and somewhat com- 

 pressed bpamches, aaid is fijeqUeatly a foot in height. There 

 are two fine speeinaeiis of this description in the Newcastle 

 Museum ; the finest of the two was found by Mr. Alder, 

 at Holy Island, and the second one by Mr. W. .T. Foster, 



