PLATE LXXIIL 201 



HALICONDRIA EDUSA, Bowerbank. 

 Plate LXXIII. 



Sponge massive, parasitical on fuci. Surface tu- 

 berculated, smooth. Oscula simple, small, and few in 

 number. Pores inconspicuous. Dermal membrane 

 strong and tough ; furnished with a dense polyspiculous 

 rete, each area containing a single pore, or, in parts 

 with a densely -felted layer of spicula, apparently with- 

 out pores. Skeleton irregular, rather dense ; spicula 

 sub-fusiformi acerate, somewhat variable in length, 

 rather stout. Interstitial membranes, tension spicula 

 few in number, slightly less, and more slender than those 

 of the skeleton. 



Colour. Dark fawn-yellow in spirit. 



Habitat. Jersey; Rev. A. M. Norman. 



Examined. From spirit. 



I received this specimen for examination from the 

 Rev. A. M. Norman ; it has been preserved in spirit in 

 the state in which it was taken from the sea. It is a 

 small, rudely pear-shaped mass, parasitical on the 

 slender stem of a fucus. It is ten lines in length and 

 seven at its greatest diameter. The surface is smooth, 

 but strongly tuberculated, and so tough that it was 

 with difficulty that I could get clean sections with a 

 sharp knife from out of the back part of the sponge for 

 examination. The oscula are small and few in number, 

 and are scarcely to be seen without the aid of a two- 

 inch lens. The most striking specific character is in 

 the dermal structure, but it is visible only when 

 mounted in Canada balsam, the quantity and density 

 of the sarcode when viewed in its natural condition 

 entirely obscuring its anatomical characters. When a 

 section from the dermal surface was mounted in balsam 

 and viewed with a microscopical power of 108 linear, 

 the strikingly characteristic nature of the dermal 

 tissues were beautifully displayed. The greater por- 

 tion of the surface was covered by a dense reticulation. 



