124 PIATE XLVIII. 



Fig. 12. — A skeleton spiculum. X 250 linear. 

 Fig. 13.— One of tLe dermal tension spicula. X 250 

 linear. 



IsoDicTYA VAEiANS, Bowevbank. 



Vol. ii, p. 281, ' Mon. Brit. Spongiadse.' 



Fig 14. — Represents the type-specimen of the 

 species in the Johnstonian collection in the British 

 Museum, marked 17^ and labelled Halichondria cinerea. 

 Natural size. 



Fig. 15.— A skeleton spiculum. x 250 hnear. 



Fig. 16. — One of the short, stout, acuate spicula. 

 X 250 linear. 



