PLATE XXIV. 



MIOROCIONA SPINULENTA, Bowerbanfc. 



Vol. ii, p. 132, ' Mon. Brit. Spongiadse.' 



Fig. 1. Represents a valve of Pecten opicularis 

 covered with a thin coat of M. spinulenta, all the dark 

 portions between the ribs of the shell having the 

 appearance of the wet pile of a brown cotton velvet. 

 The white patch on the middle of the valve is Celle- 

 pura pnmicosa. The specimen is from Weymouth 

 Bay, near the wreck of the Abergavenny. Natural 

 size. 



Fig. 2. From one of the sub-clavate, cylindrical, 

 tension spicnla of the dermal membrane. X 250 

 linear. 



Fig. 3. An attenuato-acute, entirely spined, skeleton 

 spiculum ; the base being profusely spinous. X 250 

 linear. 



Fig. 4. One of the short attenuato-acuate, entirely 

 spined, internal, defensive spicula. X 250 linear. 



Fig. 5. One of the bi dentate, inequi-anchorate, 

 retentive spicula. X 1250 linear. 



Fig. 6. An unipocilate, retentive spiculum. X 1250 

 linear. 



MICEOCIONA PLUMOSA, Bowerlank. 



Spongia plumosa, Montagu. 



Halichondria plumosa, Johnston. 



Hymeniacidon plumosa, Bowei'bank. 'Mon. Brit. Spong.,' 



vol. ii, p. 195. 

 Microciona carnosa, Bowerbank. 'Mon. Brit. Spong.,' 



vol. ii, p. 133. 



The sponges described by me in vol. ii, pp. 195 and 

 133, are decidedly the same species, and both belong 

 to the genus Microciona. 



I have fallen into this error through having examined 

 and described the first specimens of this sponge 



