PLATE XVII. 



FIG. 



!_, 2. Membranipora catenularia_, p. 134. 



3, 4. Membranipora monostachys, p. 131 ; linear 

 form. See Plate XVIII. 



5, 6, 8. Membranipora Lacroixii, p. 129; various states. 



7. , Avith marginal spines. 



