PLATE XXII. 
Synops nitida, 
Figure 1. Part of the sponge, showing the upper (or oscular) surface, and 
median plane of fracture ; nat. size. 
,, 2. Sponge, seen from below ; nat. size. 
,, 3-12. Spicules — 
Fig. 3. Oxea; x 73. 
„ 4. Ortliotrisene ; x 73. 
„ 5. Sterraster; x 73. 
,, 6. Choanosomal oxyaster ; x 73. 
„ 7. Somal spheraster ; x 73. 
1 
Fig. 8. Sterraster; x 430. 
,, 9-11. Choanosomal oxyaster and 
its modifications ; x 430. 
,, 12. Somal spheraster ; x 430. 
13. Section passing through the middle of an oscule longitudinally ; x 32. 
„ 14. Tangential slice, showing the pore-sieves ; x 32. 
„ 15-18. Longitudinal median sections through chones ; x 32. 
PAGE 
231 
