42 Palaeontographica Americana 42 



which, as in the other varieties from the same locaHty, are rather nodulous, square, and 

 have only shallow sulci. In general A. idonea from Alum Bluff has more anterior beaks 

 than in specimens from Maryland and in this last variety the short anterior and pro- 

 duced posterior parts bring the beaks well within the anterior third. The beaks are little 

 elevated, and are prosogyrate and the cardinal area is wider in front of the beaks than 

 behind, unlike the common variety. 



Conrad, himself, in 1840 stated that his species A. stillicidium was the j-oung of A. 

 ido?iea. A. slilicidiuvi Heilprin, 1881 and 1882 and stillicidum Glenn, 1904, are mis- 

 prints for A. stillicidium, and idoneus Morton, 1834, is a misprint for idonea. 



Dimensions. — Lon. + 24,-4i; alt. + 14,-40; diam. 50 mm. 



Occurrence. — Typical form from the Miocene of St. Mary's River, Marj'land, and the 

 upper bed at Altmi Bluff, Florida; the elongated variety with thirty-one ribs from St. 

 Mary's, at Windmill Point, and in Surry County, Virginia, and in the Miocene of Alum 

 Bluff, Florida; a more angular type than either of these from the Miocene of St. Mary's 

 River, Maryland. — Dall. St. Mary's Miocene of Cove Point, Langley's Bluff, St. Mary's 

 River, Maryland. — Glenn. Miocene of St. Mary's, Maryland, and the upper bed at 

 Alimi Bluff, Florida. — C. U. Museum. 



Area carolinensis Wagner 

 Plate X, Figures i, 2 



Area carolinensis Wagner, Wagner lust.. Trans., 5, p. 9, pi. i, fig. 4. 1847 (fide Dall). 



Area Carolinensis Bronn, Index Pal., Norn., p. 93, 184S; Syst., p. 281, 1849. 



Not Noelia (Area) Carolinensis Conrad, Acad. Nat. Sci. Phila., Proc. for 1862, p. 580, 1S63. 



Not Barbatia Carolinensis Conrad, Kerr's Geol. Rep. N. Car., App. A, p. 4, pi. i, fig. 11, 1S75. 



Seapharca (Scapliarca) carolinensis Dall, Wagner Free Inst. Sci., Trans., vol. 3, pt. 4, pp. 615, 632, 

 639. Pl- 33. fig. II. 1898. 



"Shell large, soHd, squarish, moderately inflated, with subcentral, prosocoelous, 

 rather elevated beaks ; left valve with about thirty ribs, with subequal interspaces, the 

 anterior ribs squarish, with a shallow median sulcus near the margin, and irregular con- 

 centric ripples; the ribs of the middle of the valve not sulcate, with less rippling, more 

 closely adjacent, the interspaces very squarely channelled; the posterior ribs smaller, 

 rounded, and more closely set; cardinal area short, rather wide, smooth, or longitudinally 

 striate, with three concentric lozenge-shaped groovings; hinge-line short, solid; the teeth 

 not interrupted, strong, about forty-five in all, the anterior more vertical, the middle 

 teeth inclining towards the middle line of the area, the posterior teeth distally, more 

 oblique and longer; margins of the shell strongly fluted. Lon. 56, alt. 55, diam. 43 mm. 

 (type specimen). 



"As this species seems never to have been described, the references in Bronn being 

 merely to Wagner's unpublished jlates, I have given a diagnosis from Professor Wag- 

 ner's original tj'pe specimen, and refigured the interior of the left valve. The shell is re- 

 markable for its squarish form, which is rather distantly approached by some specimens 

 of A. idonea. It is singular that in all the years which have elapsed since this shell was 

 collected and figured by Professor Wagner no one has recognized or described it. ' ' — Dall, 

 1898. 



