138 BRITISH SPONGES: 



under a common magnifier, more or less uneven, without pores, 

 of a grayish-white colour ; the fecal orifices scattered, small, 

 slightly raised, closed in dry specimens, and duskier than the 

 rest of the surface : internally not properly cellular, but per- 

 meated by winding canals : spicula siliceous, crystalline, slender 

 and linear, with sharp ends, but of very unequal lengths and 

 size, and either straight or curved. 



The substance of this sponge is similar to that of H. ficus. 

 It answers so exactly to Lamarck's definition of Spongia virgul- 

 tosa, excepting in being unbranched, that I cannot doubt its 

 identity with the specimens before me, but the figure of Esper, 

 (Spong. tab. 66,) to which he refers us for one of its varieties, 

 is not only excessively branched, but is apparently more loosely 

 porous than I have observed this to be. 



30. H. HiRSUTA, crustaceous, compact, granular, tcifh an 

 even villous surface ; no pores nor oscula ; spicula needle- 

 shaped. 



Plate XVI. Fig. 1. 

 Halichondria hirsuta, Flem. Brit. Aiiim. 522. 



Hah. On Escharae from deep water : coast of Banff and Zet- 

 land, Fleming. Strangford Lough, encrusting a shell, Wm. 

 Tliompson. 



" Base, when dry, very thin, granular, with long single- 

 pointed spicula, the surface hirsute with the projecting free ex- 

 tremities." Fleming. 



Sponge cinistaceous, spreading irregularly, from one to four 

 or five lines in thickness, composed of a mass of closely com- 

 pacted nearly equal granulations, of a uniform pale gall-stone 

 yellow colour when recent, the surface even and villous, with- 

 out pores or oscula : structure homologous, compact and firm, 



