PLATE V. 



Spirastrella purpurea (Lmk.) Rdl. 

 Anatomy. 



Fig. i. S. E. 948 g. Longitudinal section through a process. The arrovvs indicate the course of canals; 



a central canal ; b pseudo-cortex. Natural size. 

 Fig. 2. S. E. 948b. Transverse section through a process; a central, b peripheral canal fillecl with mud 



and detritus. Natural size. 

 Fig. 3. S. E. 426a. Longitudinal section through the pyramidal sponge; a central canal; b pseudo-cortex. 



Natural size. 

 Fig. 4. S. E. 948 g. Inner surface of the central canal, showing the systein of rugae. Slightly magnified. 

 Fig. 5. S. E. 305a. Longitudinal section; a central canal with rugae. At /; this canal is seen to originate 



by confluence of several narrower canals. Natural size. 

 Fig. 6. S. E. 931b. Longitudinal section; the arrows 1, 2, 3 indicate the course of main canals; e. e. 



depressions between fused processes. Natural size. 

 Fig. 7. S. E. 966a. Part of the surface. Natural size. [Cf. Fig. 8]. 

 Fig. 8. id. Longitudinal section following the line A B of Fig. 7. At the bottom of the hole 



is nestled an Ophiurid, Oplüactis savignyi. 

 Fig. 9. S. E. 1945. Portion of a section at right angles to the surface. The black parts represent the places 



where in life was situated the substratum. Magnified 4 or 5 times. [Cf. Fig. 1, PI. VI]. 

 Fig. 10. S. E. 1971. Longitudinal section through the top of a process. The central canal (a) is seen to 



be nearly shut at the top, leaving but a minute aperture b. After a dry specimen. 



Natural size. 

 Fig. 11. S. E. 1365. Longitudinal section through the top of a process. The central canal shows a very 



distinct system of rugae. Natural size. 

 Fig. 12. S. E. 948b. Longitudinal section through the top of a process; a central, b peripheral canal; 



X 4 a 5. 

 Fig. 13. S. E. 948 b. Transverse section through a process; a central, b peripheral canal; X 4 a 5. 

 Fig. 14. S. E. 1421. Longitudinal section. Natural size. 

 Fig. 15. S. E. 300. Longitudinal section. Natural size. 

 Fig. 16. id. Longitudinal section through a process; a central canal; b foreign (inclosed) object. 



Natural size. 

 Fig. 17. S. E. 614a. Longitudinal section through a papilla; a central canal; X 4 a 5. 

 Fig. 18. S. E. 1365. Longitudinal section through the top of a process; a central, b peripheral canal; 



X 4 a 5. 

 Fig. 19. id. Transverse section through a process; the place between the straight lines corresponds 



to fig. 1 on PI. VII; the place marked * is magnified in fig. 3 on PI. VII, the one 



marked ** in fig. 4 on PI. VII; X 4 a 5. 

 Fig. 20. S. E. 305a. Transverse section through the stem of a club; a central, b peripheral canal; c hole 



of Balanus; X 4 a 5. 

 Fig. 21. S. E. 1365. Surface view; stomata or procts; X 20. 

 Fig. 22. S. E. 1945. Surface view; stomata or procts; X 20. 

 Fig. 23. S. E. 948 g. Surface view; irregular spots, more or less transparent, showing the cavities close 



under the surface. Natural size. 



