AST. 21 TERTIARY MOLLUSKS FROM FLORIDA — MANSFIELD 9 



CARDITA (CARDITAMERA) TAMIAMlfiNSIS, new species 



Plate 3, Figures 1, 2, 3 



Description. — Shell very large, heavy, strongly inflated, and sub- 

 quadrate in outline. Middle of shell and anterior side well rounded 

 in outline; posterior side steeply descending. Sculpture of 17 ribs, 

 thin and high over the umbonal region and thick and heavy over the 

 ventral area. The ribs over tlie middle and anterior side of the shell 

 are ornamented with thin, erect, transverse lamellae and over the 

 posterior shoulder and posterior side by scabrous lamellae. The 

 lateral tooth is strong. The lower inside margin is marked with wide 

 crenulations. 



Dimensions. — Larger cotype, left valve (U. S. N. M. No. 371341) 

 measures : Length, 57 mm. ; altitude, 42 mm. ; semidiameter, 20 mm. 

 Smaller cotype, length, 46 mm.; altitude, 30 mm.; semidiameter, 

 13 mm. 



Type locality. — Tamiami Trail, 42 miles west of Miami, Fla. 



This species is very similar in outline and convexity to Cardita 

 {C arditamera) floridana Conrad, described from the Eecent fauna 

 of the coast of Florida, but in size it is twice as large as the largest 

 specimen I have seen of the Recent species. The ribs over the 

 umbonal area of the new species are much higher and thinner than 

 those on the Recent species and lack the strong beaded ornamentation. 

 C. (O.) tamiamiensis apjDears to be an ancestral form of C. -fioridana. 



Only three left valves of the new species are at hand. 



VENERICARDIA (PLEUROMERIS) PERPLANA GLADEENSIS. new subspecies 



Plate 4, Fiuhkes 2, 5 



Description. — Shell very small, moderately solid, rather low, 

 obliquely subovate, inequilateral, the anterior side being much longer. 

 Anterior side of disk much higher than posterior side. Sculpture of 

 15 closely spaced ribs, more distinct and ver}^ weakly granulated over 

 upper half of disk and indistinct over lower half. Reflected concen- 

 tric lamellae ornament the vertical half of the disk. Lunule and 

 escutcheon well defined, smooth, and lanceolate. Internal margin 

 rather coarsely crenulated. 



Dimensions.— Tio\o\^^Q, left valve (U.S.N.M. No. 371342), meas- 

 ures : Length, 3 mm. ; altitude, 3.2 mm. 



Type locality. — Tamiami Trail, 42 miles west of Miami, Fla. 



The material consists of three left valves, one of which constitutes 

 the holotype. 



F. {P.) perplana glade'ensis is most closely allied to F. {P.) p. db- 

 hreviata (Conrad), a form described from the upper Miocene at Wil-. 



