Plate XVIII. 



1. Bugula aviculariaj zooecia enlarged, p. 227. 



2. Bugula turbinata, nat. size. 2a, Zooecia enlarged, 



p. 228. 



3. Bugula flabellata, zooecia enlarged, p. 229. 



4. Bugula plumosa, zooecia enlarged, p. 230. 



5. Beania mirabilis, nat. size. 5a, Zooecia enlarged 



(after Landsborougb), p. 232. 



6. Cellaria fistulosa, nat. size. 6a, Zooecia enlarged, 



p. 234. 



