125 



PLATE XLIX. 



IsoDiCTYA ELEGANS, Bowerbank. 



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



Figs. 1, 2, 3. — Represent tliree 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. 



IsoMCTYA PAEASITICA, BowevbanL 



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



Fig. 6. — Represents the specimen in the Johnstonian 

 collection in the British Museum, designated Hali- 

 chondria fncorum, 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 6 h 

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

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

 Brit. Spougiada?..' 



Fig. 7. — One of the subfusiformi skeleton spicula. 

 X 250 linear. 



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



IsoDiCTYA MoAndeewii, Bowerhanlc. 



Vol. ii, p. 28i, ' Mon. Brit. Spongiadce.' 



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. 



