PLATE IX. 



Fig. 1. — Cinachyra harlata Sollas, | nat. size, p. 0. 



Pig. 2. — Vertical section through an oscule (x 5). 



Fig. 3. — Young specimen with one porocalyx in front and one oscule at the upper end ( X 3). 



Fig. J:. — Cortical oxea from a large specimen (x lOD). 



Figs. 5-7. — Single and double " silica pearls " (x 700). 



Figs. 8-] 2. — " Silica pearls" around which crystals of sea-salts have become deposited (x 425). 



Figs. 13, 14. — Spheroidal masses of sea-salt crystals (in optical section), which stain deeply in carmine 



(X 425). 

 Fig. 15. — Cmniella sagitta var. microsigma, vertical section of cortex in poral region, showing radial cortical 



oxeas arching over sub-dermal spaces ( x 12). 

 Fig. 16. — CranieUa sagiita var. microsigma, vertical section of cortex in oscular region showing absence of 



radial cortical oxeas ( x 12). 

 Fig. 17. — Cranidla sagitta Yav. pachyrrMbdus, flagellated chambers (x 200). 

 Figs. 18, 19.— Collar cells of the same (x 1900). 



Note. — The flagellated chambers as seen in fig. 17 are nearly denuded of collar cells, which 

 have probably become separated owing to the action of the osmic acid used in the case of this 

 specimen ; consequently the collar cells with their collars, as seen in the figures, have probably not 

 become fixed in their normal position. See remarks on p. 4. 



