St. silicensis -24- 
tendency to be somewhat swollen around the base, or is level with 
the surface of the coenenchyma. There as no projecting upper lip 
to the calices. Costae about 18 in number, distinct around the rim, 
in some instances they are short, in others they are prolonged until 
they meet those of the next calice. The limits of the zoids indi- 
cated by a fine raised line or the coenenchymal surface is granulate, 
without such a line* 
There are six stout principal septa that extend to the colu- 
mella, vestiges of the second cycle can rarely be discovered within 
the calice, but usually between each pair of costae corresponding to 
the septa of the first cycles are two costae. 
The columella is terminated by a low style, it is very much 
thickened below, where the principal septa fuse to it. 
Types * — U . S. national Museum, nine specimens, and one speci- 
men in the V/agner Free Institute of Science of Philadelphia. 
Locality .--Ballast Point, Tampa, Florida; some specimens 
which may be this species were collected by me at Blue Spring, Flint 
River, near Bainbridge, Georgia. 
Geologic horizon . — Upper Oligocene, Tampa Silex beds. 
