206 A MONOGRAPII OF THE 



this sponge is far greater than in any other species with 

 which I am acquainted. The specimen sent is a very small 

 one. It attains the dimensions of a good-sized apple. When 

 alive it is of a red-brown colour, and lives on very muddy 

 ground." 



Specimens of Hymeniacidon ficus are often, when young, 

 very like those of //. carnosa, but they may be readily distin- 

 guished by the minute inflato-cylindrical spicula which 

 abound in their dermal membranes. 



31. Hymeniacidon ficus, Bowerbank. 



Halichondkia ficus, Johnston. 



Sponge. Massive, sessile, or pedicelled, rarely coating. 

 Oscula simple, few, and scattered. Pores inconspicu- 

 ous. Dermal membrane thin, pellucid, minutely 

 granulated, abundantly supplied with minute inflato- 

 cylindrical spicula, irregularly dispersed. Skeleton. 

 Spicula, spinulate and acuate, the former exceeding the 

 latter in number. Interstitial membranes. Spicula 

 sub-attenuato-acuate, long, slender, numerous. 



Colour. Alive, gray, white, or russet red. 



Habitat. Coast of Scotland, Mr. W. C. Peach ; Coast 

 of Northumberland, Rev. A. M. Norman ; Island of Harris, 

 Hebrides, Capt. Thomas. 



Examined. In the living and dried states. 



The ficoid type of this species has been so accurately 

 described by L)r. Johnston, in his ' History of British 

 Sponges/ as to leave little more to be said on that part of 

 its history ; but, like many other British species, it varies 

 so greatly in form as to render it very difficult, if not im- 

 possible, to distinguish it by this character alone from other 

 nearly allied species ; thus, I have a little specimen which 

 has completely covered a small univalve shell precisely after 

 the manner of H. suberea, and without exhibiting the 



