70 PLATE XXVII. 



dermal membrane was well produced, but the rest of 

 its organisation was scarcely developed sufficiently to 

 characterise the species in a satisfactory manner. 



HYMERAPHIA STELLIFERA, Boiverbank. 



Vol. ii, p. 146, ' Mon. Brit. Spongiadse.' 



Fig. 4. A microscopical view of a portion of a 

 sponge exhibiting the skeleton and external defensive 

 spicula projected at various angles from the basal 

 membrane and numerous internal, defensive, clavate, 

 attenuate -cylindrical, internal, defensive spicula with 

 stellately spinous apices, in situ. X 80 linear. 



Fig. 5. A portion of the columella of a Fusus 

 completely encrusted by the sponge. Natural size. 

 Deep sea, Shetland. 



Fig. 6. A small patch of the sponge on the inner 

 surface of a valve of Docinia lincta. Natural size. 

 Deep sea, Shetland. 



Vol. i, Plate I, fig. 34, represents one of the clavato- 

 attenuato-cylindrical, apically spined internal defensive 

 spicula. X 260 linear. 



Plate xxxiv, fig. 370, in the same volume exhibits 

 a section at right angles to the basal membrane of a 

 specimen of H. stellifera, with all its spicula in situ. 

 X 108 linear. 



My indefatigable friend, Mr. Peach, when he ac- 

 companied Mr. J. Gr. Jeffreys in one of his North Sea 

 dredging expeditions, obtained a considerable number 

 of specimens of this sponge. It is by no means un- 

 common on dead shells and pebbles from 70 to 100 

 fathoms deep. 



