EXPLANATION OF THE PLATES. 671 



Fig. E. Stelletta purpurea. One of the larger specimens from 

 above, showing (e) vent. In spirit. "West Island, Torres 

 Straits, 7 fms. Nat. size. 



F. Clathria copping eri. The type specimen (dry), from 



Albany Island, Torres Straits, 3 fms. One third nat. size. 

 [The margins are slightly reduced by fracture.] F'. The 

 same ; two meshes, from front, from specimen in spirit ; 

 "West Island, Torres Straits, 3-4 fms. Nat. size. 



G. My .villa arborescens. About one half of type specimen (in 



spirit), from Port Jackson, 0-5 fms. Nat. §ize. 



H. Tethyopsis dissimilis. Larger of the two specimens from 

 Port Darwin, 7-12 fms. Inspirit. Nat. size. [Imperfect 

 above and below.] 



I. Clathria acideata. The type specimen, from Thursday 

 Island, Torres Straits, 3-4 fms. In spirit. Nat. size. 



J. Itaspailia bifurcata. The type specimen (in spirit, but 

 macerated), from Prince of Wales Channel, Torres Straits, 

 5-7 fms. Nat. size. 



"K. Esperia pellucida. One lobe of type specimen, with part 

 of incrustation involving stones &c. ; in spirit ; from Alert 

 Island, Torres Straits, 7 fms. Nat. size. 



L. ffliaphidophlus arborescens. The type specimen (dry), 

 from Friday Island, Torres Straits. Two thirds nat. 

 size. 



Plate XLI.* 



Fig. A. Hippospongia derasa. The type specimen, from West 

 Island, Torres Straits ; dry, macerated. Seen from the 

 longest side. Reduced to two thirds nat. size. 



B. Dysidea semicanalis. The type specimen, from North-east 

 coast of Australia ; dry and macerated. Reduced to one 

 half nat. size. 



* The microscopic details in this and the following Sponge-plates have been 

 in almost all cases prepared with the aid of sketches made to scale by Mr. Ridley 

 himself. 



