Figure 
?3 
53 
35 
33 
33 
PLATE XXIII. 
Synops vosmaeri, 
1. Sponge ; nat. size. 
2. Vertical median section through the sponge ; nat. size. 
13. Spicules — 
Figs. 3, 4. Somaloxeas; x 73. 
„ 5. Orth.otri8ene ; x 73. 
„ 6. Cortical oxea ; x 73. 
,,, 7. Sterraster; x 73. 
„ 8.‘ CFoanosomal oxyaster ; x 73. 
„ 9. Sterraster; x 225. 
Fig. 10. Choanosomal oxyaster ; x 292. 
„ 11. Somal spFeraster ; x 700. 
„ 12. Termination of somal oxea; 
X 292. 
,, 13. Abnormal form of oxea or 
plagiomonaene ; x 73. 
1 4. Section passing medially and longitudinally through an oscule ; x 2. 
15. Median longitudinal section through an oscular chone, showing the 
general characters of the cortex and choanosome ; x 32. 
16. Median longitudinal section through an incurrent chone ; x 32. 
17. A sieve-pore seen en face. 
18. Oblique, nearly tangential section through the outer part of the cortex, 
showing the lateral extension of the canals which extend from the 
pores to the chones. 
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