FAUNA OF ORTHAULAX PUGNAX ZONE. 127 



MODIOLUS SILICATUS Dall. 

 Plate 24, fig. 11. 



Modiolus silicatus Dall, Trans. Wagner Inst., vol. 3, pt. 4, p. 793. pi. 27, 



fig. 28, 1898. 

 Modiolus tampaensis Dall, Trans. Wagner Inst, a'oI. 3, pt. 4, p. 922, by 



inadvertence. 



Tampa silex beds, Ballast Point, Tampa Bay, Florida; Willcox 

 and Dall. U. S. Nat. Mus. No. 154349. 



MODIOLUS BLANDUS, new species. 

 Plate 20, figs. 3, 6, 12. 



Shell of moderate size, thin, rounded in front and behind, dorsally 

 subalate, margins entire with hardly any byssal gape ; valves inflated, 

 surface smooth except for incremental lines. 



Length 44, height 23, maximum diameter 21 mm. 



Ballast Point, Tampa Bay, Florida ; E. J. Post, probably from the 

 limestone overlying the silex beds. U. S. Nat. Mus., No. 165226. 



The specimen is a well preserved internal cast. 



Section BRACHYDONTES Swainson. 



Brachidontes Swainson, Malac, p. 384, 1840. Type, Modiola sulcata La- 

 marck (1819 not 1807). 



Brachydontes Fischer, Man. de Conchyl., p. 968, 1886. — Dall, Bull. U. S. 

 Nat. Mus. No. 37, p. 138, 1889. 



Semimodiola Cossmann, Cat. lUustr., vol. 2, p. 158, 1887. Type, Modiola 

 Jiastata Deshayes. 



Semimodiola Cossmann, Cat. Illustr., vol. 2, p. 158, 1887. Type, Modiola 

 sulcata Lamarck, not Risso. 



Brachydontes Dall, Trans. Wagner Inst., vol. 3, pt. 4, p. 791, 1898. 



MODIOLUS (BRACHYDONTES) GRAMMATUS Dall. 



Plate 26, fig. 4. 



Modiolus (Brachydontes) grammatus Dall, Trans. Wagner Inst., vol. 3. 

 pt. 4, p. 794, pi. 30, fig. 2, 1898. 



Tampa silex beds at Ballast Point, Tampa Bay, Florida, Dall, 

 U. S. Nat. Mus. No. 165184. A variety curtidus Dall, was obtained 

 by Burns from the lower bed at Alum Bluff, Chattahoochee River, 

 Florida. 



The variety is stouter than the type-species, more triangular, with 

 coarser and more nodulous ribs and stronger crenulations of the 

 margin. 



