HALICHONDRIA. 119 



pislortum of Lamarck, for which the figures of Esper are quot- 

 ed ; for it is little probable that an Iceland sponge should ex- 

 tend its range into the Indian ocean. 



For the following analysis of H. panicea I am indebted to my 

 distinguished friend, Dr R. D. Thompson. 



Organic matter, 



28.60 



Carbonate of lime, 



48.79 



Silica, 



19.04 



Phosphate of lime. 



2.38 



Chloride of sodium, 



1.19 



Alumina, 



100.00 



1 6. H. ^GAGROPILA, amorphous, massive, Jibro-reticular 

 and friable when dried, covered with a gauze-like skin, per- 

 forated with numerous small mammillated oscula, and a few 

 large irregidar scattered orifices ; spicula needle-shaped. 



Plate XL Fig. 1. 



Halispongia aegagropila, Scouler MSS. 



Hab. Occurs adhering to stones or to the curious coral-like 

 substances so abundant in the bay of Roundstone, Cunnamara, 

 Wm.3PColla. 



Sponge growing in large amorphous masses more than an inch 

 in thickness, very light, finn but compressible, inelastic and 

 impermeable to light, of an earthy brown colour and coarse fibro- 

 cellular texture, the fibres radiating from the base upwards and 

 formed, by their irregular inosculations, into rather large oblong 

 cells filled with a spongy parenchyma. The surface, when the 

 sponge is perfect, is covered over with a thin white cuticular 

 membrane reticulated like gauze, but not porous, through which 

 the fibres sometimes project in short spinous points. The pro- 

 per oscula are very numerous and small, and in the shape of 



