BRITISH SP0NGIADJ3. 159 



of Tenby, an ardent and successful cultivator of marine 

 natural history. 



4. Hymeniacidon fragilis, Bowerbank. 



Sponge. Branched and inosculating, sessile ; surface un- 

 even, smooth. Oscula simple, dispersed. Pores in- 

 conspicuous. Dermal membrane pellucid, spiculous ; 

 spicula fusiformi-acerate, arranged in an" irregular 

 multispicular network. Skeleton spicula fusiformi- 

 acerate, stout, irregular in size. 



Colour. — ^Alive, various shades of green and flesh colour. 

 Habitat. — Mouth of the Dart, Devonshire, Bowerbank. 

 Ewamined. — In the fresh state. 



This sponge is exceedingly common about a mile within 

 the mouth of the Dart, where an abundance of it was cast 

 up by the tide. It is extremely fragile at all times, and 

 when dry very light and friable ; the general texture of the 

 sponge is exceedmgly cavernous and irregular. Although 

 the surface is uneven and rugose, it is in no respect hispid, 

 as the dermal membrane follows every sinuation of the 

 exterior. The colour of many of the specimens when fresh 

 was more or less green, and a portion of them flesh- 

 coloured. The dried specimens generally assume a pallid 

 hue. 



5. Hymeniacidon reticulatxjs, Bowerbank. 



Sponge. Sessile, coating. Surface even, smooth. Oscula 

 congregated in marginated areas, or simple and mar- 

 ginated. Pores inconspicuous. Dermal membrane 

 translucent, spiculo-reticulate, rete irregular, strong, 

 and multispiculate. Skeleton : spicula acerate, stout, 

 and acuate, slender. 



