186 PLATE LXXIT. 



Fig. 11. One of the spicula from the dermal 

 featherly fasciculi. X 250 linear. 



Fig. 12. An average-sized skeleton spicnlum. 

 X 250 linear. 



POLYMASTIA coNiGERA, Boiverbank. 



Fig. 13. Represents the type-specimen, in the 

 cabinet of the Rev. A. M. Norman. Natural size. 



Fig. 14. One of the large external basal defensive 

 spicula. X 123 linear. This figure also represents 

 the skeleton spicula of the basal mass and the fasciculi 

 of the cloacas. 



Fig. 15. One of the smaller skeleton spicula from 

 between the primary skeleton fasciculi of the basal 

 mass. X 123 linear. 



Fig. 16. One of the secondary defensive spicula 

 from the surface of the cloacas. X 250 linear. 



HYMENIACIDON FIRMTTS, BowerbanJc. 

 Plate LXXII. 



Sponge massive, parasitical, firm and fleshy. Surface 

 smooth and even. Oscula simple, dispersed few in 

 number. Pores inconspicuous. Dermis strong and 

 tough, abundantly spiculous ; spicula acerate, stout, 

 strong and very thickly felted together, with porous 

 areas sparingly dispersed amid the felted spicula, 

 which are the same in size as those of the skeleton ; 

 dermal membrane translucent. Skeleton. Abundantly 

 spiculous, closely and compactly constructed in all 

 its parts ; spicula acerate, all stout and strong, closely 

 and irregularly disposed. Interstitial membranes trans- 

 lucent. Sarcode very abundant. 



Colour. In spirit, dull ochreous yellow. 



