PLATE XXII. 



FIG. 



1. Megapora ringens, p. 172. 



2. Membranipora minax, p. 169. 

 2 a. , avicularium. 



2 b, 2 c. , 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. 

 G. , var. a (quadrata) . 



