125 



PLATE XLIX. 



ISODICTYA ELEGANS, Boiverlank. 



Vol. ii, p. 283, ' Mon. Brit. Spongiadas.' 



Figs. 1, 2, 3. Represent three portions of the 

 type-specimen of the species in the cabinet of the 

 Rev. A. M. Norman. Natural size. 



Fig. 4. A skeleton spiculum. X 250 linear. 



Fig. 5. One of the tension spicula, from the inter- 

 stitial membranes. X 250 linear. 



ISODICTYA PARASITIC A, Bowerbank. 



Vol. ii, p. 287, ' Mon. Brit. Spongiadse.' 



Fig. 6. Represents the specimen in the Johnstonian 

 collection in the British Museum, designated Hali- 

 chondria fucorum, and marked 51, 7, 25 225, from 

 Dundee, by Mr. Gardner. The portions of sponge 

 opposite a a a a are I. parasitica ; those opposite b b 

 I. Clarkei. For a description of the latter species I 

 must refer the reader to page 330 of vol. ii, ' Mon. 

 Brit. Spongiadse.' 



Fig. 7. One of the subfusiformi skeleton spicula. 

 X 250 linear. 



Fig. 8. A tension spiculum. X 250 linear. 



ISODICTYA MCANDEEWII, Bowerbanlc. 



Vol. ii, p. 284, ' Mon. Brit. Spongiadse.' 



Fig. 9. Represents the type- specimen presented to 

 me by Mr. McAndrew. Natural size. 



Fig. 10. One of the stout, short, skeleton spicula. 

 X 250 linear. 



