92 PLATE XXXVI. 



an elongated pedestal and has apparently been sepa- 

 rated from its basal attachment while alive. Natural 

 size. 



Fig. 8. One of the long slender skeleton spicula. 

 X 150 linear. 



Fig. 9. One of the small slender spinulate spicula 

 of the interstitial membranes. X 150 linear. 



HYMENIACIDON FIOUS, Bowerbank. 



Vol. ii, p. 206, ' Mon. Brit. Spongiadse.' 



Fig. 10. A very fine mature specimen of the species 

 on the outer surface of half of an old bivalve shell. 

 I dredged it in Grilter Sound, near Tenby ; it is of a 

 compressed form like that of a dried fig, not ex- 

 ceeding about five eighths of an inch in thickness. 

 Natural size. 



Fig. 11. A small specimen which has apparently 

 been based on a univalve shell which it has entirely 

 enveloped from the Island of Harris, Hebrides, by 

 Captain Thomas, R.N. Natural size. 



Fig. 12. A specimen entirely enveloping a small 

 univalve shell from the coast of Scotland by Mr. C. 

 W. Peach. Natural size. 



Fig. 13. A spinulate, skeleton spiculum. X 150 

 linear. 



Fig. 14. -An acuate, skeleton spiculum. X 150 

 linear. 



Fig. 15. A sub -attenuate, acuate, slender spiculum 

 of the interstitial membranes. X 150 linear. 



Fig. 16. One of the minute inflato-cylindrical 

 spicula of the dermal membrane. X 150 linear. To 

 give an idea of the relative size of these spicula as 

 compared with those of the skeleton. X 150 linear. 



Fig. 17. The same spioulum. X 530 linear. 



