133 



Fig. 17. Ceratopora jncksoni. Co) The type specimen natural size : (b) longitudinal 

 section of a calyx, showing bud, and absence of cysts in the upper part, x 2}4 : (c) cross- 

 section of calyx, and bud, x 2i^ ; (d, e) cross-sections of corallites, showing the cysts and the 

 central living chamber, also the spines or trabeculas. x 5 ; (/,) longitudinal section of a cor- 

 allite, x 5. The dark shading indicates cavities filled with mud, the light shading those filled 

 by crystalline calcite. (Original.) 



