128 PLATE L. 



spiculum, from the interstitial membranes. X 250 

 linear. 



ISODICTYA JUGOSA, Bowerbank. 



Vol. ii, p. 296. ' Mon. Brit. Spongiadte.' 



Fig. 11. Represents the type-specimen of the 

 species from Shetland, in the cabinet of the Rev. A. 

 M. Norman. Natural size. 



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



Fig. 13. One of the tension spicula, from ihe inter- 

 stitial membrane. X 250 linear. 



Fig. 14. A simple bihamate spiculum, from the 

 dermal membrane. X 530 linear. 



ISODICTYA GREGORII, Bowerbank. 



Vol. ii, p. 301, ' Mon. Brit. Spongiadse.' 



Fig. 15. Represents the type-specimen of the 

 species from the Moray Frith. Natural size. The 

 sponge coats the inner surface of the shell for nearly 

 half the inner portion towards the hinge of the shell. 



Fig. 16. A skeleton spiculum of about the average 

 size. X 250 linear. 



Fig. 17. One of the tension spicula of the inter- 

 stitial membranes. X 250 linear. 



ISODICTYA SIMPLEX, Bowerbank. 



Vol. ii, p. 294, ' Mon. Brit. Spongiadse.' 



For the figure of this species I must refer the reader 

 to Plate XLIV, fig. 6, of the present volume. 



Fig. 18. Represents one of the skeleton spicula. 

 X 250 linear. 



In January, 1870, I received five specimens of 

 sponges for examination from the Rev. A. M. Norman, 

 who found them at low water mark in Strangford 



