HALICHONDRIA. 145 



talium entalis with their animals alive, from a lislierman at Har- 

 tlepool, who dredged them up in his trawling-net from very- 

 deep water, I observed a kind of sponge which has, 1 believe, 

 been confomided with the Alcyonium Ficus, Zm." J. Hogg. 

 Coast off the Isle of Man, E. Forbes. 



Sponge obovate or pear-shaped, sometimes bulging from a 

 narrow stalk, from one to fully three inches in height, and one 

 inch and a-half in diameter, either bulbous or compressed late- 

 rally, very compact, firm, incompressible and inelastic, of a 

 greyish-white colour, the surface smooth, either punctured or 

 without visible pores, and without fecal orifices, or these are 

 very few, small and scattered. The texture of the interior is 

 likewise very close and compact, and exhibits a very imperfect 

 cellulosity, but it is permeated with some short and narrow ca- 

 nals that have no certain distribution, and do not reach the 

 surface. 



H. Ficus may be compared, and in general aptly, to a half- 

 ripe Puff"-ball, (Lycoperdon), but the sponge is of a less yield- 

 ing and denser texture. It is composed of acicular siliceous 

 spicula matted together and crossed in every direction amid 

 the gelatinous parenchyana which forms the basis and aggluti- 

 nating medium. These spicula are very slender and rather long, 

 varying extremely, however, in their degree of slenderness, and 

 while some are straight, others are curved, and others are 

 flexuose : They are more pointed at one end than at the other, 

 but, from their brittlencss, entire spicula are with difficulty ob- 

 tainable. Milne-Edwards says, when speaking as I think of the 

 same species, that the parenchyma which surrounds them contains 

 some carbonate of lime. I found that dilute muriatic acid ren- 

 dered the surface of the sponge a shade whiter ; and on im- 

 mersing a piece of the interior in the acid a scarcely perceptible 

 and evanescent effervescence was produced ; but I am satisfied 



K 



