244 NEW Y RK STATE MUSEUM 



antelateral region ; anterior margin similarly curved, rounding to the sical 

 margin, which is short (about one half the hight of the shell) and arched. 

 The angle between it and the posterior margin is obtuse and rounded. 

 Beneath the beak and just in front of it are three strong and short plica- 

 tions bending upward to the margin, comparable to the single riblet that 

 appears in similar position in several other species of the genus. Very 

 faint radial lines are also visible over the posterior and median parts, and 

 concentric lines occur on the anterior slope, taking the form of regular 

 festoons or rings. 



This species is well characterized by its form, subumbonal radii, and 

 the concentric undulations on the anterior slope. All the specimens 

 observed are from the same locality. 



Habitat. Genesee province ; Chautauqua subprovince. Walnut creek, 

 Forestville, Chautauqua co. N. Y. 



Lunulicardium suppar sp. nov. 



Plate 3, fig. 6-10 



Shell suborbicular in outline, rotund. Beak central, directed anteriorly. 

 Umbones full. Length and width equal. Surface highly convex, greatest 

 elevation being attained near the center, whence the slope is rather gradual 

 and regular toward the base, but much more abrupt both anteriorly and 

 posteriorly and more so posteriorly than anteriorly, making a bulged and 

 sharply deflected surface on the posterior face. The sical margin is short, 

 oblique and transverse, making a very large angle with the anterior margin 

 at the beak, not extending for one half the higrht of the shell, and incurved 

 or concave. The sicae are set off from the body of the shell by a sharp 

 groove, are clearly defined, narrow, extended outward, and not downward 

 or inward, and do not bear a smooth surface. The angle between the sicae 

 and the anterior margin of the valve is large and prominent. 



The surface of the shell is entirely covered with fine, obscure radial 

 lines, which become broader toward the periphery. All are flattened, and a 

 few of those on the anterior slope are larger than the rest, and are sepa- 

 rated by broader furrows. The sicae also bear similar radial lines. Low 



