672 EXPLANATION OF THE PLATES. 



Fig. C. Dgsidea digitifera. The type specimen, from Albany 

 Island, 8 fms. ; in spirit ; growing over Hydroid zoophyte. 

 Nat. size. 



D. Gladochalina diffusa. One of the type specimens, from 



Singapore, between tide-marks ; in spirit, llcduced to 

 two thirds nat. size. d. Portions of primary and secon- 

 dary fibre of vertical section, x 95. d! '. Detached 

 spicule, x 190. 



E. Hymeniacidon agminata. The type specimen, from Port 



Jackson, 0-5 fms. ; in spirit. Reduced to two thirds nat. 

 size. 



F. Raspailia clatlirata. Basal portion of type specimen, from 



Thursday Island, 3-4 fms. Nat. size. 



g. Euspongia officinalis, var. cavernosa. Vertical section of 

 type (dry) specimen, from Torres Straits, x 38. 



h. Psammopemma densum, var. suhfibrosa. Vertical section of 

 type (spirit) specimen, from Torres Straits, x 38. [The 

 surface faces to the right.] 



i. Cladochalina nuda. Portion of vertical section of type 

 specimen, from Alert Island, showing the contained spi- 

 cules, x 190. 



j. C. nuda, var. abrujotispicula. Spicules of type specimen 

 from Thursday Island. X 190. 



Tc. Chalina monilaia, portion of primary fibre of vertical 

 section of type, from Port Jackson, showing the contained 

 spicules, x 370. h'. An isolated spicule, x 370. 



I. Cladochalina subarmigera, portion of primary and secon- 

 dary fibres of vertical section, I', spicules, of type specimen, 

 from Warrior Reef, x 190. 



in. Toxochalina folioides, fibre of main skeleton as seen in 

 vertical section, in'. Skeleton-spicule, x 68. m". Tri- 

 curvate flesh-spicule, x 370. Prom specimen from Port 

 Darwin. 



