83 



PLATE XXXIII. 



HYMENIACIDON MAMMEATA, Bowerbank. 



Vol. ii, p. 170, ' Mon. Brit. Spongiadse.' 



Fig. 1. Represents the type-specimen in the 

 cabinet of the Rev. A. M. Norman. Natural size. 



Fig. 2. One of the large, fusiforari, acuate, skeleton 

 spicula. X 150 linear. 



Fig. 3. A slender, acuate, tension spiculum, from 

 the dermal membrane. X 150 linear. 



Fig. 4. A fusiformi-acuate, external, defensive 

 spiculum. X 150 linear. 



Since the publication of this species, p. 170, vol. ii, 

 I have obtained a fine specimen of it from the Diamond 

 Ground, off Hastings. It is in the form of a com- 

 pressed dried fig, two inches in diameter and half an 

 inch in thickness at its distal portion, from which 

 numerous mammae are projected, varying in height 

 from three to five lines, and about one line and a half in 

 diameter near the base. The sponge is attached by 

 about two thirds of its under surface to the external 

 surface of a fragment of Pecten maximus. 



HYMENIACIDON CONSIMTLIS, Bow&rbank. 



Vol. ii, p. 172, ' Mon. Brit. Spongiadse.' 



Fig. 5. Represents the type- specimen of the species 

 from Belgrave Bay, Guernsey. In the collection of 

 the Rev. A. M. Norman. Natural size. 



Fig. 6. One of the skeleton spicula. X 150 linear, 



