PLATE XL VI. 



pro. 



1. SERTULARELLA POLYZONIAS, p. 235, nat. size. From a 



drawing by Mr. T. West. 



1 . A portion, magnified (T. H.). 1 b. The gonotheca 

 (T.H.). 



2. SERTULARELLA GAVE, p. 237, nat. size. 



2 a. A portion, enlarged. From drawings by Mr. Alder. 



