106 PLATE XLIII. 



retentive spicula, of the dermal membrane. X 530 

 linear. 



Fig. 11. — A tridentate, equi-ancliorate, retentive 

 spiculum, from the dermal membrane. X 630 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. 



Halichondkia subdola, Soiverbanh. 



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



Fig. 14. — Represents the type-specimen from Yazon 

 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, fi'om 

 the dermal membrane. X 150 linear. 



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



