EXPLANATION OF THE PLATES. 669 



Pig. B.. Stelispdngus implexus. The most symmetrical of tliree 

 specimens from coral-reef, Port Molle ; dry. Nat. size. 



C. SipTionoehalina bullata. Left-hand half of largest dry speci- 



inen from Port Curtis, showing two completed tubes, and 

 behind them (c) the margin of an incomplete one. Eeduced 

 two thirds iiat. size. 



D. Eeniera testudinaria. Small part of large dry specimen from 



4 fms.. Port Denison, showing the lobes and ridges which 

 characterize the surface of the species. Eeduced to two 

 thirds nat. size. 



E. Shieochalina spathulifera. The type (dry) specimen from 



Thursday Island, 4-5 fms. Eeduced to two thirds nat; 

 size. [The lower part overrun by the filiform stolons of a 

 Hydroid Zoophyte.] 



P. B. canalis. Dry specimen, one of the types, from Port Dar- 

 win, 8-12 fms. [The lower end of the figure shows that one 

 end of the canaliform Sponge has been broken off and the 

 centre of the specimen coated by a calcareous Polyzoon 

 {Oellejaora).'] Eeduced to two thirds nat. size. 



G. Toxoehalina robusta. Terminal branches of a spirit-speci- 

 men from Port Jackson ; upper surface, showing vents. 

 Eeduced to two thirds nat. size. 



H. Cladochalina suharmigera. Part of a specimen in spirit 

 from "Warrior Beef, Torres Straits, seen from above, 

 showing vents and short and scanty spines. Nat. size. 



I. Gelliodes Jibulata. One of the larger and more ramose 

 specimens, exhibiting several anastomoses of the branches. 

 Dry ; from Thursday Island, 3-5 fms. Eeduced to two 

 thirds nat. size. 



J. Pellina muricata. Part of the type specimen, in spirit, from 

 Port Darwin, between tide-marks, showing serial arrange- 

 ment of the hispid cloacal tubes to form a wall-like ridge. 

 Nat. size. 



K. Ehaphidophlus procerus. The largest spirit-specimen from 

 Port Darwin, 7-12 fms. [The basal portion includes a 



