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TERTIARY FAUNA OF FLORIDA 



I 103 



This seems to be the Pacific coast representative of C. medium, but has 

 much wider ribs. 



Section Trigoniocardia Dall. 



This group seems especially characteristic of the Middle American and 

 Antillean region to which it is, so far as known, confined. It is an offshoot 

 of the Fragum group starting in the Eocene and more or less abundantly repre- 

 sented to the recent fauna, which contains, on the Atlantic side, C. antillarum 

 Orbigny (1845, + C. ceramidum Dall, Blake Rep., i., p. 269, pi. 4, fig. 6, 1886) 

 and on the Pacific side C. graniferum Broderip and Sowerby, 1829; C. ala- 

 hastrum Carpenter, 1857, and C. obovale Sowerby, 1833. 



Of species belonging to this group which have been described from the 

 Tertiary there are C. castum Guppy, 1866, of the Eocene of Manzanilla, Trini- 

 dad; C. haitense, Sowerby, 1849, of the St. Domingo, Curaqao, and Jamaica 

 Oligocene; C. galvestonense Harris, 1895, from the Upper Miocene of the 

 deep well at Galveston, Texas; and C. callopleurum Gabb, 1881, from the 

 Pliocene of Costa Rica. These appear to be well-founded species, and it is 

 now practicable to add materially to the list. Hemicardia afUnis Nelson, 1870, 

 from the Tertiary of Peru, is compared by the author to C. obovale, but is 

 unfigured and insufficiently described. 



Cardium (Trigoniocardia) alicula n. sp. 



Plate 40, Figure 12 ; Plate 48, Figure S- 



Oligocene of the Ballast Point silex beds, Tampa, Florida, Dall; of the 

 lower bed at Alum Bluff ; and the marls of the Chipola River, Calhoun County, 

 Florida, Burns. 



Shell obliquely subtriangular, elevated, narrow, truncate behind the beaks, 

 rounded above in front and pointed below; beaks high, carinated behind the 

 keel defining the posterior area; posterior area with eight low, flat ribs, the 

 upper ones broader; body with twelve similar but larger ribs separated by 

 narrow cross-striated channels deeper near the keel and almost obsolete in 

 front; on top of the ribs when perfect are rounded pustules, sparse, very 

 fragile, and usually worn off; the pustules on the ribs of the posterior area 

 are more elongate, oblique, and rarely arcuate ; margin fluted internally, hinge 

 strong. Alt. when fully mature, 19, Ion. 14, diam. 14 mm. 



The specimen first figured (pi. 40, fig. 12) is worn and has lost its pustules, 

 being only a pseudomorph in silica; the subsequent figure (pi. 48, fig. 5) 

 illustrates the unworn sculpture. 



