684 SYSTEMATIC PALEONTOLOGY 



LEGUMEN PLANULATUM Conrad 

 Plate XL, Figs, 5-7 



Solemya planulata Conrad, 1853, Jour. Acad. Nat. Sci., Phila., 2d ser., vol. 



ii, p. 274, pi. xxiv, fig. 11. 



Legumen ellipticus Conrad, 1858, Ibidem, vol. iii, p. 325, pi. xxxiv, fig. 19. 

 Legumen appressus Conrad, 1858, Ibidem, p. 325. 

 Legumen appressa Meek, 1864, Check List Inv. Fossils, N. A., Cret. and 



Jur., p. 15. 



Legumen elliptica Meek, 1864, Ibidem. 

 Legumen planata Meek, 1864, Ibidem. 



Legumen ellipticus Conrad, 1868, Cook's Geol. of New Jersey, p. 727. 

 Legumen appressus Conrad, 1868, Ibidem. 



Legumen planulatus Gabb, 1876, Proc. Acad. Nat. Sci., Phila., p. 304. 

 Legumen planulatum Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 



184, pi. xxv, figs. 3, 4. 



Legumen appressum Whitfield, 1885, Ibidem, p. 185, pi. xxv, figs. 6-8. 

 Legumen ellipticum Whitfield, 1885, Ibidem, p. 184, pi. xxv, fig. 5. 

 Legumen planulatum Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 17. 

 Legumen appressum Johnson, 1905, Ibidem. 

 Legumen ellipticum Johnson, 1905, Ibidem. 

 Legumen planulatum Weller, 1907, Geol. Survey of New Jersey, Pal., vol. 



iv, p. 612, pi. Ixix, figs. 3-7. 



Description. " Elliptical, compressed, sides flattened ; end margins 

 rounded; hinge and basal margins nearly parallel." Conrad, 1853. 



Type Locality. Monmouth County, New Jersey. 



Shell very thin and porcellanous, much compressed, transversely ellip- 

 soidal in outline, slightly expanding posteriorly; dorsal and ventral mar- 

 gins subparallel; posterior extremity strongly arcuate, anterior end of 

 shell slightly constricted directly in front of the umbones; the lateral 

 margin evenly and strongly convex; lunule and escutcheon not defined; 

 umbones very low and compressed with sharp and prosogyrate apices 

 placed within the anterior third; external surface adorned with a sharp 

 incremental sculpture, almost obsolete in the umbonal region and along 

 the extreme dorsal margin, sharpest and most regular near the anterior 

 ventral margin; radial sculpture not developed; ligament submarginal, 

 seated on a nymph not quite half as long as the posterior dorsal margin ; 

 cardinals three in number in each valve ; the anterior and middle cardinals 

 of the right valve thin, laminar and rather short, diverging beneath the 



