442 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



they fuse and produce a continuous wall with only an occasional 

 perforation. 



The columella is papillary, about two papillae being larger than 

 the others. In worn specimens it is very prominent, appearing com- 

 pressed styliform. 



Locality and geologic occurrence. — Florida, Caloosahatchee River, 

 collected by W. H. Dall; Shell Creek, Florida, collected by Doctor 

 Griffith; Pliocene. 



Type.—No. 325184, U.S.N.M. 



Paratype.—'^o. 325185, U.S.N.M. 



The most striking differences between S. pliocenica and S. radians, 

 to which it probably has the greatest affinity, are its larger and 

 much shallower calices. S. californica Vaughan from the Pliocene of 

 Carizo Creek, California, is a nearly related species. 



7. SIDERASTREA HILLSBOROENSIS, new species. 



Plate 117, fig. 2. 



Description of the type. — Corallum massive, composed of long, 

 prismatic corallites. No entire corallum is available for description, 

 but the lieight may certainly exceed 10 cm. 



Diameter of a large corallite, 5.5 mm.; of a smaller one, 4 mm. 

 The two measurements indicate the range in diameter. 



Septa normally in 4 cycles, the fourth cycle complete or almost 

 complete, arranged as follows: The six primaries extend directly to 

 the columella and are free from fusion with other septa; the seconda- 

 ries also extend to the columella, near which the tertiaries fuse to 

 sides of the included secondaries; the quaternaries fuse to the sides 

 of the included tertiary system about halfway between the wall and 

 the columella. The fourth cycle is incomplete in a few quarter sys- 

 tems of some calices. The primaries and secondaries are of about 

 equal thickness; the tertiaries slightly thinner, and quaternaries 

 still thinner. The number of dentations on the septal margins was 

 estimated from the number of septal trabeculae, as the septal margins 

 are not preserved; it is 9 or 10. 



Synapticulae well developed; in each interseptal loculus; three or 

 four are usually conspicuous between the wall and halfway from 

 it to the columella. Although the upper septal margins are not pre- 

 served, it seems probable that there is a flattened area between 

 adjacent calicular fossae in perfect specimens. 



Columella false, but strongly developed by the axial fusion of the 

 inner ends of the primary and secondary septa. 



Localities and geologic occurrence. — Station No. 4890, Tampa brick- 

 yard, 5 miles northeast of Tampa, Florida, in the Alum Bluff forma- 

 tion, G. C. Matson collector, the type; in the Alum Bluff formation 

 at station No. 3836, near Alachua, Florida, T. W. Vaughan collector; 



