TRANSACTIONS OF WAGNER 

 624 - < 



TERTIARY FAUNA OF FLORIDA 



regularly spaced and correspond to elevated concentric lines in harmony 

 with the lines of growth; the posterior dorsal slope is bounded by rounded 

 ridges radiating from the beaks ; the posterior cardinal margin is elevated and 

 angular with more or less of a depression between it and the radial ridge on 

 each side ; the byssal foramen is wide and irregular ; the hinge-line is long 

 and straight; the teeth, vertical and very small medially, are sometimes obso- 

 lete in the middle of the hinge; distally they become rather distant and quite 

 oblique, as well as larger; the internal margin, though irregular, is not fluted. 

 Lon. of adult 51, alt. 25, diameter 20 mm. 



This species is distinguished from B. marylandica by its smaller altitude, 

 its coarser and more prominent sculpture, and more irregular hinge ; the 

 beaks are also more anterior. 



Barbatia (Calloarca) arcula Heilprin. 

 Plate 33, Figure 4. 

 Area arcula Heilprin, Trans. Wagner Inst., i., p. 118, pi. 16, fig. 65, 1887. 



Oligocene of the Ballast Point silex beds, Tampa Bay, Florida; Willcox. 



Shell subovate, thin, inflated, the beaks low and prosogyrous; the cardinal 

 area narrow and very closely and minutely furrowed longitudinally, the fur- 

 rows showing a slight angle behind the beaks ; sculpture of close set, fine radial 

 ribs, rather regularly imbricated at successive lines of growth ; on the poste- 

 rior dorsal slope are six or eight nodulous larger ribs ; the beaks are situated 

 a little behind the anterior third ; bj-ssal foramen narrow, very anterior ; hinge 

 with a few large A-shaped teeth at fhe ends, the middle teeth vertical, small, 

 or even obsolete mesially ; margins of the valve slightly or not at all crenu- 

 lated by the sculpture. Length of shell 47, of hinge-line 30, height 31, 

 diameter 26 mm. 



This species is very evenly and regularly fluted at the imbrications, dif- 

 fering in that respect from any of the other species mentioned here. It is 

 notable also for its inflated and thin valves and the bluntly truncate posterior 

 end, though the latter may be abnormal. 



Barbatia (Calloarca) cuculloides Conrad. 

 Area euculloides Conr., Fos. Tert. Form., No. 3, p. 37 (not fig'cl), 1833. 

 Byssoarea lima Conr., Journ. Acad. Nat. Sci. Phila., 2d Ser., i., p. 125, pi. 13, fig. 23, 



1848 ; not Barbatia lijiia Rve., P. Z. S., 1844. 

 CticiMcearca lima et euculloides Conr., Am. Journ. Conch., i., p. 11, 1865. 



