Rev. A. M. Norman on a new Sponge from Jersey. 299 



Dysideafragilis (Montagu). A very curious form of this spe- 

 cies occurred between tidemarks at Tobermory. It incrusts 

 stones with a thin layer, and is almost entirely devoid of 

 the particles of sand which are generally found abundantly 

 incorporated in the substance of the Sponge. 



It will be seen in the foregoing list how strongly the 

 northern influence shows itself in the Sponges of this part of 

 the west of Scotland ; at the same time I think that we may 

 perhaps see, in the presence of Leuconia nivea, Grantia ensata, 

 and Chalina seriata, evidence of the same intermixture of 

 southern and northern forms among the Porifera which we 

 know to occur in other classes of the Hebridean inverte- 

 brata. 



I take this opportunity of publishing the description of a 

 new sponge from Jersey. The specimen was procured in 

 1859 ; and having recently examined it I found it to differ 

 from other species known to me, and therefore sent it to Dr. 

 Bowerbank for his opinion. He has kindly supplied me with 

 the following description : — ■ 



" Desmacidon copwsus, Bowerbank, n. sp. 



" Sponge sessile, coating. Surface rugged and uneven. Oscula 

 simple, dispersed. Pores inconspicuous. Dermis subcrusta- 

 ceous ; dermal membrane pellucid, profusely spiculous, fur- 

 nished with a stout irregular network; rete polyspiculous, 

 areas abundantly supplied with spicula ; tension- spicula tri- 

 curvate, acerate, small and slender, equicurvate, rather nume- 

 rous ; retentive spicula simple, contorted, and reversed biha- 

 mate, very numerous and rarely biumbonate-bihamate, large 

 and stout ; also inequidentato-palmate anchorate, and bidentate 

 inequianchorate, both forms very minute and few in number, 

 dispersed. Skeleton irregular and very open ; fibre stout ; 

 spicula subclavate, fusiformi-acerate, stout, and very fusiform ; 

 areas large and profusely spiculous ; tension-spicula subcla- 

 vate, fusiformi-acerate, long and slender, exceedingly numerous 

 and closely matted together ; also tricurvate acerate, small and 

 slender, few in number ; retentive spicula the same as in the 

 dermal membrane, but more copiously distributed. Gemmules 

 membranous, aspiculous. 



" Colour in the dried state cream-white. 



"Hob. Jersey (Rev. A. M. Norman, 1859). 



" Examined in the dried state." 



22* 



