PLATE XV. 
Tigure 
J) 
Figs. 1-19. Antliastra pyriformis, . 
1. Sponge ; nat. size. 
2. Sponge, cut through vertically ; nat. size. 
3-11. Spicules — 
?5 
Fig. 3. Oxea; x 39. 
,, 4, 5. Dicliotriaenes; x 39. 
„ 6. Protriaene or plagiotri»ne; x 39. 
„ 7. Anatrisene; x 39. 
,, 8. Cladome of an anatriaene; x 180. 
Fig. 9. Cladome of an abnormal triaene, with four 
cladi; x 180. 
,, 10. Anthaster; x 430. 
,, 11. Chiaster; x 430. 
12. Part of a vertical median section, showing the ectosome and the character of the chones ; x 15. 
1 3. Transverse section through the wall of a canal, , showing the epithelial cells raised into 
projections hy the actines of the asters, which are not seen, owing to the preparation 
being mounted in glycerine ; beneath the epithelium granule cells are shown ; x 400. 
14, 15. Transverse sections through the ectosome, showing a plexus of collencytes, some of which 
are directed towards the epithelium, like palpociis ; x 292. 
16. Fusiform cells, which sometimes occur wrapping round the megascleres ; x 292. 
17. Diagram of a velum, showing collencytes radiating from the wall of the canal in which it 
occurs. 
PAGE 
146 
18. Transverse section of the symbiotic Diatom — Amphora arclieri; x 300. 
19. Longitudinal section of the preceding; x 300. 
Figs. 20-27. Anthastra communis, . . . . 
20. Cribriporal roof of a subdermal cavity, lower surface seen era /ace / x 180. 
21. Transverse section through the wall of a canal, showing the epithelium raised into projections 
by the actines of the chiasters ; x 360. 
22. Two epithelial cells seen e?z /ace, one with a contained chiaster ; x 360. 
23-27. Spicules — 
Fig. 23. Oxea; x 49. Fig. 26. Anthaster; x 360. 
,, 24. Dichotrisene; x 49. ,, 27. Chiaster; x 360. 
„ 25. Anatriaene; x 49. 
140 
Figs. 28-32. Pilochrota tenuispicula, .... 127 
„ ^ 28. Sponge ; nat. size. 
„ 29-31. Spicules— 
Fig. 29. Oxea; x 32. 1 Fig. 31. Chiaster; x 430. 
,, 30. Orthotrisene; x 32. I 
„ 32. Transverse section through the cortex, in the region of a chone ; x 7. 
J) 
33-39. Spicules — 
Figs. 33-39. Stryphnus unguiculus. 
Fig. 33. Somal oxea; x 32. 
,, 34. Dichotrisene; x 32. 
,, 35. Cladal end of dichotrisene; x 180. 
Fig. 36. Cladome of dichotrisene, seen m face ; 
X 180. 
,, 37. Choanosomal oxyaster; x 292. 
,, 38, 39. Somal amphiasters ; x 292. 
195 
)> 
Figs. 40-46. CoralUstes tliomasi. 
40-46. Spicules — 
Fig. 40. Dichotrisene ; x 180. 
,, 41. Cladome of dichotrisene seen from below ; 
X 180. 
Fig. 42. Young form of dichotrisene ; x 180. 
,, 43. Strongylospires ; x 430. 
,, 44-46. Spirasters ; x 292. 
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