PLATE XX. 
PAGE 
Figs. 1-13. Piloclirota gigas, , . . . .124 
Figure 1. Sponge ; nat. size. 
,, 2-6. Spicules — 
Fig. 2. Isoactinate oxea ; x 39. I Fig. 4. Orthotrisene ; x 39. 
„ 3. Anisoactinate oxea ; x 39. | 5, 6. Chiaster ; x 360. 
,, 7. Part of a transverse section through, tlie sponge ; x 16. 
,, 8. Section through part of the choanosome, showing the pale granular cells ; x 360. 
„ 9. Part of section through one of the fibrous hands of attachment ; x 292. 
,, 10. Median longitudinal section through one of the fibrous hands of attachment, the upper end 
of the figure includes a part of the body of the sponge ; x 1 6. 
„ 11. A part of the foregoing section, more highly magnified, the contorted lines indicate wrinkled 
fusiform cells; x 540. 
,, 12. A part of section shown in fig. 10, including the surface of attachment ; x 292. 
„ 13. Another portion of the same section, to show more darkly stained protoplasmic cells in 
association with the pale granular cells ; x 292. 
Figs. 14-21. Cydonium glariosus, . . . .223 
„ 14. Sponge; nat. size. 
,, 15-21. Spicules — 
Fig. 15. Orthotrisene ; x 28. 
„ 16. Protrisene ; x 28. 
,, 17. Anatriaene ; x 28. 
,, 18. Sterraster; x 225. 
r ig. iH. (jnoanosomai oxyaster ; x ow. 
,, 20. Subcortical spberaster ; x 540. 
„ 21. Oladal end of anatrisene ; x 180. 
Fig. 22. Cydonium eosaster, ..... 225 
22. Transverse section through an excurrent canal and surrounding choanosome ; x 125. 
