PLATE V. 



PAGE 



Representation of entire specimen and isolated portions of Exiplectella suherea, 



Wyv. Thomson, . . . .73 



Fig. 1. Restoration of the whole sponge, formed by combining the various frag- 

 ments ; natural size. 



Fig. 2. Oxyhexaster from the trabecular framework of the side wall ; x 500. 



Fig. .3. Fragment of a rosette, probably not belonging to Euplectella suherea, liut 

 extrinsically intruded; x 500. 



Fig. 4. Fragment of a gastral floricome ; x 500. 



Fig. 5. Fragment of a dermal floricome ; x 500. 



Fig. 6. Part of a diact lying close to the distal ray of a large principal hexact ; 

 x500. 



Fig. 7. Rough diact with rounded extremities and with four tubercles markedly 

 projecting from the axial cross ; from the circular membrane of a 

 parietal aperture ; x 500. 



Fig. 8. Fragment of a discohexaster, probably not belonging to Euplectella 

 suherea, but extrinsically intruded ; x 500. 



Fig. 9. Fragment of a doubtful rosette, perhaps extrinsically intruded ; x 500. 



Figs. 10, 11. Ends of various median-sized spicules ; x 500. 



Fig. 12. Inside of the lateral wall ; natural size. 



Fig. 13. Hypodermal pentact ; x 50. 



Fig. 14. Long comital diact; x 50. 



Fig. 15. Principal pentacts in natural disposition ; x 3. 



Figs. 16-20. Median-sized loose spicules of the parenchyma of the wall ; x 50. 



Fig. 21. Fragment of a diact with four projecting central tubercles; x 500. 



This plate was executed under Sir Wyville Thomson's direction, 



