Plate 10. 



Fig. 1. Sclerothamnopsis compressa. From a photograph ; \. 

 " 2. Bathyxiphus, sj). From a photograph. A small piece has been taken out, and 



the two parts fastened together with a pin ; \. 

 " 3. Sclerothamnopsis compressa. From a photograph ; \. 

 " 4. Hexactinella lahyrintliica. Scopula ; upper and lower ends ; x 600. 

 " 5. Chonelasma calyx F, E. Sch. (sp.?). From a photograph. Sponge wall cutaway 



so as to show septum ; \. 

 " 6. Hexactinella labyrinthica. From a photograph ; \. 

 " 7. " " Group of slender, spinose hexacts and pentacts, 



partially fused ; x 300. 



