PLATE XXII. 



1. MEGAPORA RINGENS, p. 172. 



2. MEMBRANIPORA MINAX, p. 169. 



, avicularium. 



2 a. 



2l> } 2c. 



-, young cells. 



3. MEMBRANIPORA CORNIGERA, p. 164; from an old 



specimen, showing the structure of the upper 

 portion of the aperture. 



4. MEMBRANIPORA ROSSELII, p. 166. 



5. MEMBRANIPORA TRIFOLIUM, p. 167. 



6. , var. a (QUADRATA). 



