154 BRITISH SPONOIADJE. 



being plunged in fresh water. In its natural state it 

 feels soft and pulpy. On being dried it assumed 

 precisely the same appearances as those presented by 

 the types figured in Plate XCI, vol. iii, ' Mon. Brit. 

 Spongiadse.' The size of the specimen was two inches 

 and a half long, greatest breadth one inch and a 

 quarter, and thickness about half an inch." 



68. ISODICTYA IMPLICITA, Boiv., ii. sp., iv, Plate XVI, figs. 

 714. 



" Sponge massive, parasitical amidst Nullipora poly- 

 morplia. Surface smooth. Oscula simple, minute, 

 dispersed. Pores inconspicuous. Dermal membrane 

 spiculous ; tension spicula dispersed or subfasciculate, 

 slender attenuato-acuate, same size and form as those 

 of the skeleton; and stout attenuato-acuate, both 

 forms basally spinous ; retentive spicula minute, bipo- 

 cellate-anchorate, few in number, and rarely minute 

 inequi - anchorate. Skeleton irregular and much 

 complicated ; primary lines multispiculous ; spicula 

 slender, attenuato-acuate, basally incipiently spinous, 

 with an intermixture of stout attenuato-acuate ones, 

 basally strongly spinous. Secondary lines irregular, 

 varying from unispiculous to multispiculous ; spicula 

 same as in the primary lines. Interstitial membranes 

 sparingly spiculous ; spicula same as in the dermal 

 membrane. Sarcode, dark purple. 



" Colour. In the dried state, dark purple. 



" Habitat. Westport Bay, Ireland, in 5 fathoms ; 

 Rev. A. M. Norman. 



" Examined. In the dried state. 



