BRITISH SPONGIADiE. 161 



spiculate and strong ; spicula acerate, large. Skeleton. 

 Abundantly spiculous ; spicula large and long. 



Colour. Dried, lurid pale green. 



Habitat. Coast of Northumberland, Rev. A. M. Nor- 

 man. 



Examined. In the dried state. 



I received a single specimen of this sponge from the 

 Rev. A. M. Norman. It entirely enveloped a cluster of 

 Tubularia two and a half inches long, and was, at its 

 broadest part, nearly an inch in width. A cursory observer 

 would be very liable to mistake it for a specimen of Ilali- 

 chondria panicea in its dried state, the reticulated surfaces 

 of each being very similar ; but the difference in their ana- 

 tomical structure readily distinguishes them. The same 

 reticulated surface also exists in dried specimens of H. 

 reticulatus, but the dissimilarity in colour, and the disper- 

 sion of the oscula, instead of being congregated in mar- 

 ginated areas serves to distinguish them. The anatomical 

 structure of each is also very similar, and they are not 

 readily separated by description alone, but when the 

 structures of the two species are microscopically com- 

 pared, the difference in the size of the spicula, and the 

 shorter and stronger character of the whole of the struc- 

 tures of If. fallaciosus compared with those of H. reticu- 

 latus is strikingly apparent ; an adult spiculum of the 

 former being to a full grown one of the latter as five to 

 three, with a corresponding increase of diameter. 



7.Hymeniacidon albescens, Bowerbanh. 



Halichondma albescens, Johnston. 



Sponge. Massive, sessile ; eliminating one, or rarely more, 

 irregularly cylindrical virgultose branch, or branches 

 from its apex ; branches occasionally dividing into 

 two. Surface smooth. Oscula simply dispersed, 



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