EXPLANATION OF PLATE IV. 



Fig. I. — Spicules of Mopsea jdumacea, sp. no v. ; from the 

 specimen figured on Plate vii. 



Fig. 2. — Spicules of Mopsea repens, sp. nov. ; from the 

 specimen figured on Plate viii. 



Fig. 8. — Spicules of Plumarella australis, sp. nov\ ; from the 

 specimen figured on Plate x. 



Fig. 4. — Amphilaphis plumacea, Thomson and Mackinnon. 

 Photograph of a specimen 17- 5cm. in height, from 

 the south east coast of Australia. 



Fig. 5. — CtenoceUa pectinata (Pallas). Branches showing 

 distinct median furrow. Photograph of a specimen 

 from eight miles east of Sandon Bluff, Queensland, 

 35-40 fathoms. 



