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897 

 TERTIARY FAUNA OF FLORIDA 



arm of the right cardinal in line with the ventral lamina, both very short. 

 Lon. 50, alt. 34, diam. 15 mm. 



This species is perhaps as near S. dcliuubis as any other, but is smaller 

 and more compressed. The lamina: are quite short and not striated. 



Spisula (Hemimactra) delumbis Conrad. 



Pl.ATK 27, Fl<;iIRF. 26. 



Ma,-lra ,/i-/iiiii/iis Conr., Fos. Sh., p. 26, pi. 11, 1832; Ten. Fos., p. 27, pi. 15, fig. i, 



1838; 1'roc. Acad. Nat. Sci. 1'liila. 1862, p. 372, 1863. 

 Mtiilra I'ir^iniana Conr., Am. Journ. Conch., iii., ]>p. 188, 269, pi. 22, fig. 4, 1867. 



Chesapeake Miocene of the James River, Virginia, at Smithficld and 

 Suffolk ; of the York River, at Yorktown, Virginia, and in Maryland, at St. 

 Mary's City ; Burns and Harris. 



This fine species was early described by Conrad, who, many years after, 

 obtaining specimens of S. marylanttiea, perpetrated one of his characteristic 

 blunders by re-describing the old species and leaving the new one still name- 

 less, his intention, of course, being to do just the reverse. 



Spisula (Hemimactra) marylandica n. s. 

 PLATE 28, FIGURE 5. 



Chesapeake Miocene of Jones's Wharf, Patuxent River, Maryland, of 

 St. Mary's River, Maryland, Burns ; and of Walton County, Florida, L. C. 

 Johnson. 



Shell large, subovate, thin, inflated, with a nearly smooth surface, marked 

 chiefly by incremental and obsolete radiating lines ; beaks high, subcentral, 

 adjacent ; anterior end excavated above, rounded in front, posterior sloping to 

 a bluntly pointed end behind; anterior dorsal area rather smooth and deeply 

 impressed; posterior area somewhat depressed, striated, flexuous, with three- 

 obscure, elevated lines, extending from the unibo to the margin outside of the 

 area ; base arcuate ; pallial sinus rather narrow, extending nearly to the middle 

 of the shell, bluntly pointed in front; hinge strong, with a large oblique chon- 

 drophore, very short, smooth lateral lamin;u, and the anterior arm of the right 

 cardinal tooth coalescenl with the ventral lamina. Lon. 90, alt. 67, diam. 

 40 mm. 



This fine species is at once differentiated from S. ilclituibis by its more 

 equilateral and inflated shell, and by having instead of only one three elevated 

 lines radiating backward from the beak. 



