FAUNA OF ORTHAULAX PUGNAX ZONE. 53 



last whorl comprising most of the shell, moderately convex, aper- 

 ture narrow, wider in front; outer lip thickened, especially toward 

 the middle, its posterior end somewhat protracted on the whorl be- 

 hind the suture; posterior sinus of the aperture rounded, body with 

 a thin wash of callus; pillar short, carrying four prominent sub- 

 equal plaits, the anterior of which is coincident with the twisted edge 

 of the pillar; canal very short and wide. Height 7.7, maximum 

 diameter 4.7 mm. 



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



Type specimen from the Post collection, U. S. Nat. Mus. 165061. 



MARGINELLA BELLULA Dall. 

 Plate 16, fig. 9. 



Marginella bella var. hfUnhi Dall, Trans. Wagner Inst., vol. 3. pt. 1, p. 53, 

 pl. 4, fig. 8c, 1890. 



Tampa silex beds, at Ballast Point, Tampa Bay, Florida ; Xewman, 

 Burns, and Dall. U. S. Xat. Mus. No. 1G5053. 



MARGINELLA INEPTA Dall. 

 Plate 15, fig. 2. 



Marginella hcUa var. inepta Dall, Trans. Wagner Inst., vol. 3. pt. 1, p. 53, 

 pl. 4, fig. Sd, 1890. 



Tampa silex beds, at Ballast Point, Tampa Bay, Florida ; Newman 

 and Dall. U. S. Nat. Mus. No. 112101. 



MARGINELLA FAUNULA Dall. 

 Plate 16, fig. 14. 



Marginella faunnla Dall. Trans. Wagner lust., vol. 3, pt. 1. p. 53, pl. 4, 

 fig. 9 ft, 1890. 



Tampa silex beds, at Ballast Point, Tampa Bay, Florida; rare; 

 Dall. U. S. Nat. Mus. No. 11210-3. 



The habit of this species is somewhat like M. fauna Sowerby, but 

 the form is more like M. hellvla. 



MARGINELLA ELEGANTULA Dall. 



Plate 16, fig. 11. 



Marginella elcganiula Dall, Trans. Wagner Inst., vol. 3. pt. 1, p. 54. pl. 4, 

 fig. 7, 1890. 

 Tampa silex beds, at Ballast Point, Tampa Bay, Florida; rare: 

 Dall. U. S. Nat. Mus. No. 1112104. 



The characters of this species point to it as a probable precursor of 

 such forms as M. margarifa and M. haematita Kiener, but the Plio- 

 cene link in the series has not yet been detected. 



