712 
DR W. T. GORDON ON CAMBRIAN ORGANIC REMAINS 
Fig. 14. Hexactinellid spicule of ordinary type. (Slide S. 36c, x 20.) 
Fig. 15. Thalamocyathus tubavallum. Transverse section of cup. a, b, stirrup-pores. (SlideS. 125, x 10.) 
Fig. 16. Epiphyton fasciculatum. Transverse section through thallus, showing numerous tubules filled 
by a matrix of granular calcite. (Slide S. 140, x 26.) 
Plate II. 
Thalamocyathus trachealis, Taylor, sp. 
Fig. 17. Transverse section of young cup, showing a considerable number of septa but no infilling by 
callus growth into the central cavity. (Slide S. 88, x 28.) 
Fig. 18. Transverse section of largest specimen obtained, a, a, pores on outer wall. (Slide S. 4, x 5'5.) 
Fig. 19. Transverse section of cup, shown in last figure, at a lower level. Internal ring-platforms 
prominent. Fringe of peg-like outgrowths from lower surface of shelf at a. See PI. Ill, fig. 26. 
(Slide S. 22, x 22.) 
Fig. 20. Transverse section of cup to show a complete ring- platform. At a the platform is complete, 
at b only the outer rim is indicated. Septal pores at c. (Slide S. 23, x 22.) 
Fig. 21. Longitudinal section of outer wall to illustrate the porous structure. (Slide S. 18, x 21.) 
Fig. 22. Longitudinal section of inner wall, a, pores ; b, ring-platform cut vertically ; d, septa ; c, peg- 
like denticles on lower surface of platform. (Slide S. 14, x 21.) 
Fig. 23. Longitudinal section to show septal pores, a, pores on outer wall ; b, peg-like projection from 
under side of ring-platform ; c, septum with pores. (Slide S. 15, x 22.) 
Fig. 24. Longitudinal section of Australian specimen from Ajax Hill, Beltana, South Australia, a, pores 
on outer wall; b, peg-like projections on lower side of ring-platform ; c, septum with pores. (Slide S. 161, 
x 22.) 
Fig. 25. Transverse section of a specimen showing coralloidal structures filling in the central cavity. 
(SlideS 26, x 7-5.) 
Plate III. 
Fig. 26. Thalamocyathus trachealis. Transverse section of cup, part a of PI. II, fig. 19, highly 
magnified to show the row of peg-like projections, s, septum ; p, septal pore ; a, row of pegs in action. 
(Slide S. 22, x 90.) 
Fig, 27. T. flexuosus. Transverse section of fragment of large cup. (Slide S. 47, x 3.) 
Fig. 28. Longitudinal section of inner wall of T. flexuosus. Stirrup-pores indicated at b, (Slide 
S. 46, x 9.) 
Fig. 29. T. flexuosus. Longitudinal section of outer wall, s, septa indicated between pore rows, i.e. no 
stirrup-pores. (Slide S. 45, x 9.) 
Fig. 30. T. infundibulum. Longitudinal section through inner wall. (Slide S. 91, x 10.) 
Fig. 31. T. ichnusse. Oblique longitudinal section showing pores on inner wall and septa. (Slide 
S. 58, x 10.) 
Fig. 32. Spirocyathus atlanticus. Transverse section of cup. (Slide S. 35c, x 11.) 
Fig. 33. Coscinocyathus endutus. Longitudinal section of young cup. i.w., inner wall with pores ; 
o.w. , outer wall; s, septum with pores; t, tabula. (Slide S. 29, x 26.) 
Fig. 34. G. fultus. Oblique section of young cup showing fixing process ( r.pr .). b, base on which the 
cup is fixed (it is part of a cup of Metaldetes plicatus) ; o.w., outer wall much thickened ; c, central cavity. 
Fig. 35. Protopharetra radiata. Complete transverse section of largest cup obtained. (Slide S. 29, x 9.) 
Fig. 36. P. polymorpha. Longitudinal section of central cavity. The complete specimen is figured 
at PI. VI, fig. 66. Cavity filled in by proliferations from inner wall and dissepimental tissue, p, pores on 
inner wall. (Slide S. 2, x 10.) 
Plate IV. 
Fig. 37. Spirocyathus atlanticus. Transverse section of cup near top. (Slide S. 37, x 9.) 
Fig. 38. S. atlanticus. Oblique section showing that the septa are more like a meshwork of rods than 
a plate perforated by pores, and thus accounting for the disconnected type of septum as seen in transverse 
section. (Slide S. 48, x 2’5.) 
