PLATE XIII. 



KIG. 



1. SERTULARIA ABIETINA, p. 75, of the natural size. 1* A 



portion of the same magnified. 



2. SERTULARIA TAMARISCA, p. 74, of the natural size, from a 



specimen presented by Mr. Bean. 



3. A portion of the preceding specimen magnified. 



4. The Vesicle of SERTULARIA TAMARISCA, copied from Ellis' 



Corallines, pi. i. No. 1, A. 



