372 A MONOGRAPH OF THE 



5. Chalina gracilenta, Bowerbank. 



Sponge. Coating, parasitical. Surface even when young, 

 nodulated when old, asperated. Oscula simple, dis- 

 persed. Pores inconspicuous. Dermal membrane 

 pellucid, aspiculous, or with a few tension spicula 

 only. Skeleton. Spicula fusiformi-acerate, minute, 

 abundant in all parts of the fibre. Tension spicula 

 same as those of the skeleton, few in number. 



Colour. — Alive, yellow ; when dried, light brown. 



Habitat. — Torbay, Mrs. Griffiths; Scarborough, Mr. 

 Bean ; coast of Northumberland, Rev. A. M. Norman ; 

 Hastings, J. S. Bowerbank. 



Examined. — In the living and dried states. 



I received two specimens of this sponge from Mrs. 

 Griffiths, who found them enveloping the stems of Codium 

 tomentosum ; neither of them were an inch in length, and in 

 the dried condition did not exceed half a line in thickness. 

 The skeleton is slender, and the general aspect of the 

 sponge is very light and delicate ; with a two inch lens the 

 surface is seen to be asperated by the projection of the 

 surface fibres. On examining a thin slice immersed in 

 water, with a power of 260 linear, the membranous struc- 

 ture presented a comparatively thick and granulous appear- 

 ance, and but very few spicula could be detected within its 

 substance, but on subsequently mounting the same frag- 

 ment in Canada balsam, the spicula both in the fibres and 

 the membranes became much more distinctly apparent. 

 There is no distinction visible between the spicula of the 

 two organs, but they are so minute as to render it neces- 

 sary to use a power of about 400 linear to define their form 

 decisively. 



I also received two specimens from the Rev. A. M. 

 Norman. One of them was very thin, not exceeding half a 



