PLATE XII. 
PAGE 
Figs. 1-28. Anthastra pulclira, . . . .138 
Figure 1. Sponge; nat. size. 
„ 2-22. Spicules — 
Fig. 2. Oxea; x 49. 
„ 3. Orthotrisene; x 49. 
,, 4. Anatrisene; x 49. 
,, 5. Asters; x 49. 
,, 6. Chiaster; x 292. 
,, 7-13. Various forms of anthaster; x 292. 
,, 14, 15. Chiasters; x 292. 
,, 16. Young form of anatrisene; x 292. 
,, 17. The same, more advanced; x 292. 
Fig. 18. The same, still more advanced; x 292. 
,, 19. Young form of orthotrisene (the 
actines are more porrectate than 
in the adult); x 292. 
,, 20, 21. Young forms of anthaster; x 292. 
,, 22. Young form of orthotrisene, the 
cladome seen from above, showing 
the remains of the tylus. 
23. Vertical median section through, the sponge ; x 4. 
24. Section through a part of the ectosome, showing a pore communicating with a suhdermal 
cavity; x 73. 
2-5. Section through the outer part of the ectosome ; x 292. 
26. Section through the ectosome and part of the choanosome to show the suhdermal cavities ; 
X 1.6. 
27. Tangential section through the ectosome, showing lateral extension of the suhdermal 
cavities; x 15. 
28. Section showing flagellated chambers ; x 576. • 
Figs. 29-33. Myriastra simpUcifurca^ . . . .114 
29. Sponge ; nat. size. 
30-33. Spicules — 
Pig. 30. Oxea; x 32. i Fig. 32. Anatrisene; x 32. 
,, 31. Orthotrisene; x 32. | ,, .33. Chiasters; x 292. 
Figs. 34-43. Myriastra davosa, . . . 116 
34. Sponge; nat. size. 
35-38. Spicules — 
Fig. 35. Oxea; x 32. I Fig. 37. Anatrisene; x 32. 
,, 36. Dichotrisene; x 32. ' ,, 38. Chiasters; x 292. 
39. Vertical median section through the sponge ; x 11. 
40. Vertical section passing tangentially through the walls of the cloaca ; x 11. 
41. Section through a part of the ectosome ; x 292. 
42. Section showing the sarcencytes of the sarcenchyma ; x 292. 
43. Cladome of an anatrisene, showing the extension over it of the sclerohlast ; x 292. 
