PLATE XII. 



FIG. 



1. SERTULAKIA NIGRA, p. 68, of the natural size. From a 



specimen from Mr. R. Q. Couch. 



2. A portion of the same magnified. 



3. SERTULARIA PINNATA, p. 69, of the natural size. From a 



specimen given me by Mrs. Griffiths. 



4. A portion of the same magnified. 



