106 PLATE XLIIT. 



retentive spicula, of the dermal membrane. X 530 

 linear. 



Fig. 11. A tridentate, equi-anchorate, retentive 

 spiculum, from the dermal membrane. X 530 linear. 



Fig. 12. A simple, bihamate, retentive spiculum, 

 from the dermal membrane. X 530 linear. 



Fig. 13. One of the forcipiform tension spicula, 

 from the interstitial membranes. X 250 linear. 



HALICHONDEIA SUBDOLA, Boiverbank. 



Vol. ii, p. 247, ' Mon. Brit. Spongiadse.' 



Fig. 14. Represents the type-specimen from Vazon 

 Bay, Guernsey, of the natural size, and in the dried 

 state. In the cabinet of the Rev. A. M. Norman. 



Fig. 15. One of the slender acuate spicula, from 

 the dermal membrane. X 150 linear. 



Fig. 16. A skeleton spiculum. X 150 linear. 



