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1425 



TERTIARY FAUNA OF FLORIDA 



Shell subovate, very much inflated, inequilateral, the beaks nearly anterior, 

 decurved, low ; surface sculptured with about thirty subequal, rough riblets, 

 separated by subequal channelled interspaces ; the ribs are crossed by numerous, 

 somewhat irregular emphatic lines of growth, between which they are more 

 or less imbricate ; the ribs are sometimes squarish and towards the base more 

 rounded or even obsolete, closer and finer behind ; the lunule is deep and small ; 

 ' the outline of the shell varies, some of the specimens being shorter and higher 

 than others ; the inner margin is sharply and closely crenulate. Length 32, 

 height 30, diameter 32 mm. 



The fossils of this horizon are poorly preserved, but no other species known 

 from our Tertiary approaches this in inflation. The interior is inaccessible, 

 but the specimens, such as they are, apparently abundant. 



Venericardia gregglana n. sp. 



V enericardia alticostata var. Harris, Bull. Am. Pal., ii.. p. 247, pi. ii., fig. i, 1897. 

 Cardita decusata Tuomey, 2d Biennial Rep. Ala., p. 271, 1858; not of Lamarck, 1807. 



Lower bed at Gregg's Landing, Alabama, in the Chickasawan or Lignitic 

 stage of the Eocene. 



Shell large, but relatively thin, with high beaks, but the line of the inner 

 margins suborbicular ; the ribs are narrow and high, about thirty-four in 

 number, flatfish above and even overhanging a little laterally, with flat, denti- 

 form imbrications directed tozvards the wnhones; the interspaces are subequal 

 or slightly narrower than the ribs and channelled. The ribs in the young shell 

 are accompanied by a narrow, elevated riblet on each side, but the adult has 

 the posterior riblet generally obsolete towards the ends of the shell, and both 

 riblets obsolete in the middle of the disk below ; the beaks are prosogyrate, the 

 lunule small and convex, the hinge rather light, and the inner margin sharply 

 crenulate. It reaches a maximum height of 55 mm. and a diameter of 36 mm. 



This form is rarely well preserved, but the sculpture, when perfect, is a 

 clue to differentiate it from any other of our Tertiary species. It has a general 

 resemblance to V. Smithi Aldrich, but is without the rostration or the minor 

 sculpture of that species. 



Venericardia nasuta n. sp. 

 Plate 53, Figure g. 

 Eocene of Conecuh County, Alabama ; L. C. Johnson. 



Shell very inequilateral, elongate, solid, with large prosogyrate, nearly an- 

 terior beaks ; anterior end short and rounded, posterior produced, decurved, 



