146 BRITISH SPOXGIAD.E. 



spicula belonging to the sponge. A few adventitious 

 spicula of much greater size from other sponges were 

 embedded on its surface and amid its structures.' 



59. ISODICTYA SCITULA, Bow. t n. sp., iv, PI. IV, figs. 

 13, and PL IX, figs. 13. 



" Sponge massive, sessile. Surface even, minutely 

 but strongly hispid. Oscula simple, dispersed, minute. 

 Pores inconspicuous. Dermal membrane spiculous, 

 spicula dispersed ; tension-spicula acuate, few in num- 

 ber, same size as those of the skeleton ; retentive 

 spicula bidentate equi-anchorate, very minute and 

 slender, rather sparingly dispersed. Skeleton pri- 

 mary lines multispiculous; secondary lines, mostly uni- 

 spiculous ; rather irregularly disposed ; spicula acuate, 

 small. Interstitial membranes pellucid, aspiculous. 



" Colour. In the dried state, light ochreous yellow. 



" Habitat. Roundstone Bay, Ireland ; Rev. A. M. 

 Norman. 



" Examined. In the dried state. 



" I received several specimens of this pretty little 

 sponge from my friend the Rev. A. M. Norman for 

 examination ; they were seated amid the branches of 

 small specimens of Nullipora polymorplia, and none of 

 them exceeded the size of a large pea. To the un- 

 assisted eye the surface appears even and smooth, and 

 it is only when a portion of the surface is mounted in 

 Canada balsam and viewed with a power of about 100 

 linear, that it is seen to be abundantly and strongly 

 hispid, the hispidation being produced by the projec- 

 tion of the distal terminations of the primary fibres of 



