% 
400 Fossil Shells of Tampa Bay. 
margin very oblique and straight from umbo to extremity ; sum- 
mits very prominent ; cardinal teeth very robust; basal margin 
slightly arched posteriorly ; inner margin crenulated. 
Ballast Point, Tampa Bay. 
Little of the shell remains, which exhibits those radiating fur- 
rows common to all the chalky specimens of the genus in a fos- 
sil state. A cast of the hinge shews the form of the teeth, and an 
impression in the rock copies the exterior characters of the 
shell. 
Venus floridana.—Triangular, with concentric distant ribs; 
umbo broad, elevated ; ligament margin very oblique, 
straight; valves slightly flattened or compressed pos- 
teriorly, extremity angulated. 
Occurs with the preceding. 
Plagiostoma ? 
An indeterminate species with numerous approximate somewhat 
squamose radiating undulated striz. 
Occurs with the preceding, 
Nucouta. 
Nueula tellinula.—Longitudinally ovate, with central beaks ; 
anterior end narrow, slightly truncated at the extremity, 
“xxii” anterior dorsal margin straight and very oblique. 
Oceurs with the preceding. 
CYTHEREA. 
- Cytherea floridana.—Oval, inequilateral, rounded at the ends ; 
ligament margin slightly curved; basal margin 
y, rounded. 
. Z Occurs with the preceding. 
This seems to have been a smooth and polished species, but 
none of the shell remains. . 
Baanvs. 
~ Balanus humilis.—Suboval, not elevated ; arene large, 
Eg somewhat diamond shaped; valves with ‘rather fine pg 
tudinal approximate sulci. 
hor ap Falls. 
