308 SYSTEMATIC PALEONTOLOGY 



Length, 88 mm. ; height, 78 mm. ; diameter, 27 mm. 



Occurrence. — St. Mary's Formation. St. Mary's River, Cove Point. 



Collections. — Maryland Geological Survey, Johns Hopkins University. 



Venus campechiensis var. cuneata (Conrad). 

 Plate LXXXII, Fig. 3, Plate LXXXIII, Fig. 2. 



Mercenaria cuneata Conrad, 1867, Proc. Acad. Nat. Sci. Phila., voL xix, p. l."9 



(name only). 

 Mercenaria cuneata Conrad, 1868, Amer. Jour. Conch., vol. iv, p. 278, pi. xx, fig. 1. 

 Venus campechiensis Dall, 1908, Trans. Wagner Free Inst. Sci., vol. iii, pt. vi, pp. 



131.5, 1317, 1318 (in part). 



Description. — " Subtriangular, ventricose medially, slightly flattened 

 or contracted above the umbo; outline of the disk nearly straight below 

 the middle ; surface with coarse concentric lines ; posterior side cuneiform, 

 lower half of posterior margin nearly rectilinear, extremity subacute; 

 inner margin minutely crenulated. 



" This species may be distinguished from M. mercenaria in being less 

 oblique, proportionally shorter and more acute at the posterior extremity, 

 and in having a more elongated anterior cardinal tooth." Conrad, 1868. 



This species is readily distinguished by its short, massive and broad 

 hinge area, its great proportionate height, its massiveness, and its nearly 

 symmetrical triangular outline. The dorsal and posterior slopes meet in 

 an abrupt curve. 



Length, 112 mm. ; height, 102 mm. ; diameter, 37 mm. 



Occurrence. — St. Mary's Formation. Cove Point, St. Mary's Eiver, 

 Choptank Formation, Governor Eun, 2 miles south of Governor Eun, 

 Flag Pond, Jones Wliarf, Pawpaw Point, Peach Blossom Creek, Dover 

 Bridge, Greensboro, Cordova. Calvert Formation (?). Charles 

 county {fide Cope). 



Collections. — Maryland Geological Survey, Johns Hopkins University. 



Venus campechiensis var. capax (Conrad), 

 Plate LXXX, Fig. 1, Plate LXXXI, Fig. 1. 



Venus capax Conrad, 1843, Proc. Acad. Nat. Sci. Phila., vol. i, p. 324. 

 Venus capax Conrad, 1845, Fossils of the Medial Tertiary, p. 68, pi. xxxviii, fig. 4. 

 Mercenaria capax Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. .574. 

 Mercenaria capax Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 9. 

 Venus campechienses Dall, 1903, loc. cit. supra. 



Description. — " Cordate, suborbicular, ventricose, with concentric 

 Jamelliform prominent lines; posterior margin curved, extremity trun- 



