958 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Dalmanella rogata (Sardeson) ScHUCHERT and Cooper, Mem. Peabody Mus. Nat. Hist., 
vol. 4, pt. I, p. 120, pl. 17, figs. 2-5, 7, 13, 31, 1932. 
Figured specimens.—48701a,b. 
Horizon and locality—Upper Decorah (Ion shale—Fucoid bed) and lower 
Prosser (Vellamo bed) in Minnesota: At Spring Valley, Fillmore County ; 
Cannon Falls, Goodhue County ; St. Paul; Kenyon, Goodhue County ; Rochester, 
Olmsted County ; Fountain, Fillmore County; Warsaw, Rice County. 
Same formation in Wisconsin: At Mineral Point, Mineral Point (30’) Quad- 
rangle ; Highland, lowa County. 
Auburn chert in Missouri: $ mile east of Auburn, Elsberry (15’) Quadrangle. 
PAUCICRURA SUBPLANA Cooper, new species 
Plate 159, D, figures 14-20 
Shell of about moderate size for the genus, slightly wider than long; sides 
and anterior margin strongly rounded; anterior commissure faintly sulcate. 
Finely costellate and with about 70 costellae around the margin of the pedicle 
valve. 
Pedicle valve fairly strongly convex in lateral profile and with the maximum 
convexity in the posterior half; anterior profile roundly subcarinate and strongly 
arched; umbonal region narrowly swollen; median region swollen and with a 
steep anterior slope; sides flattened but steep ; interarea short, curved ; beak small. 
Brachial valve nearly flat in lateral profile; anterior profile slightly convex 
and depressed medially by a shallow, narrow sulcus; sulcus originating at the 
umbo, broad and shallow, almost obsolete at the front margin. Flanks slightly 
swollen and with short, gentle slopes to the margins. 
Measurements in mm.— 
Brachial Hinge 
Length length Midwidth width Thickness 
FplOty@el Ure <A eet srs 10.0 9.2 10.6 6.5 4.5 
Paratype. Lass ke eke vs 0.1 8.5 10.0 6.4 4.2 
Types.—Holotype: 123237a; figured paratype: 123237b. 
Horizon and locality—Martinsburg formation (part with Brongniartella= 
Salona) in Virginia: On County Highway 617=910, 0.15 mile north of Green 
Mount Church, Broadway (15’) Quadrangle. 
Discussion.—This species is characterized by its fine costellae and the nearly 
plane brachial valve. It is separated from Dalmanella sculpta, with which it 
occurs, by these features. Although the interior is at present not known, the 
species is referred to Paucicrura because of the nearly flat brachial valve. It 
differs from P. virginica in being more circular and in having much finer costel- 
lae. The species is suggestive of P. rogata, but that species has a wider hinge 
and distinct shoulders as well as stronger ornamentation. 
PAUCICRURA VIRGINICA Cooper, new species 
Plate 159, A, figures 1-5; plate 160, A, figures I-10 
Shell of about usual size for the genus, slightly wider than long, subquadrate 
to subcircular in outline; hinge wide, greatest width at about the middle; sides 
