196 A MONOGRAPH OF THE 



one end only. Osciila simple, large, abundant, dis- 

 persed. Pores inconspicuous. Skeleton : spicula 

 acuate, entirely spined, stout ; and occasionally without 

 spines. Internal defensive spicula attenuato-acuate, 

 entirely spined. Interstitial membranes. Tension 

 spicula like those of the dermal membrane ; and with 

 attenuato-acuate entirely spined defensive spicula; 

 retentive spicula like those of dermal membrane, very 

 abundant. 



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

 Locality. — Coast of Devonshire, Montagu and Mrs. 

 Griffiths. 



Examined. — In the dried state. 



The anatomical structure of this sponge is very interest- 

 ing. The skeleton is exceedingly diffusive. The plumose 

 appearance at the surface of the sponge in Montagu's type 

 specimen is produced by the projection of a few of the 

 terminal fasciculi of the skeleton, partially enclosed within 

 the dermal membrane and projecting above the surface, in 

 some cases to the extent of three or four lines ; but this is 

 not the natural condition of the sponge. Montagu's 

 specimen has been very much weathered, and a considerable 

 portion of the dermal membrane has been destroyed, but 

 fortunately for our knowledge of this species my kind 

 Mend, the late Mrs. Griffiths, of Torquay, who assi- 

 duously collected and studied the British sponges for many 

 years, has, with her accustomed liberality, sent me the 

 whole of her valuable collection for examination, and 

 among them there are three specimens in a fine state of 

 preservation, having the surface thickly studded with 

 mammillated elevations, which are entirely enclosed by the 

 dermal membrane, and which therefore do not possess the 

 plumose character, whence the name is derived by Montagu. 



The dermal membrane is pellucid, and is, comparatively, 

 of considerable thickness, and very similar to the general 

 mass of the interstitial membranes. It is abundantly 

 furnished with flat bundles of numerous large acerate 



