464 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
excludes it from that genus. The scar is smaller than usual in Mimella. The 
adductor scars are not elevated on a median callosity, but a low callus rim ex- 
tends around the anterior margin of the field. Furthermore, a small ridge extends 
for a short distance anterior to the median point of the muscle field. 
The undistorted types figured, although large specimens, are not the largest 
in the collections. A crushed individual from the locality northwest of Browns- 
burg measures 36.5 mm. long and 37.5 mm. wide. The specimen is somewhat 
lengthened and narrowed by the crushing, but in perfect condition the shell 
would nevertheless be larger than any other specimen known. 
DOLEROIDES REGULARIS Cooper, new species 
Plate 95, C, figures 21-28 
Shell small to medium size for the genus, subrectangular in outline; hinge 
fairly wide but narrower than the midwidth; greatest width at about the middle; 
sides rounded ; anterior commissure rounded; anterior commissure rectimargi- 
nate; costellae narrowly rounded with interspaces about equal to the costellae, 
about II in 5 mm. at the front margin; fasciculate along the margin, particularly 
on the flanks. 
Pedicle valve about equal in depth to the brachial valve, moderately convex in 
lateral profile with the greatest convexity in the posterior half; anterior profile 
broadly convex; umbonal and median regions swollen, somewhat flattened an- 
teriorly ; lateral regions moderately convex and with long, gentle slopes to the 
margins. Apsacline; dental plates strong, bounding moderately deep umbonal 
cavities ; muscle field elongate, diductor scars long; adductor track with a short 
anterior projection. 
Brachial valve fairly strongly convex in lateral profile; broadly convex in 
anterior profile and with median region somewhat swollen; sulcus originating 
on the umbo, shallow and short, defined distinctly to the middle after which it 
merges somewhat with the swollen anterior half. Median and umbonal regions 
strongly swollen; lateral slopes steep and moderately long. 
Measurements in mm.—Holotype, length 13.4, brachial length 12.9, width LS 9, 
hinge width 13.9, thickness 8.6. 
Types.—Holotype: 118005a; figured paratypes: 110646a,f; unfigured para- 
types: 110646b-e; figured specimen: 110592a. 
Horizon and locality—Wardell formation (top 40 feet) in Virginia: On Vir- 
ginia Highway 610 at the southwest base of Paint Lick Mountain, Pounding Mill 
(15’) Quadrangle. 
Wardell formation in Tennessee: On the north side of the road 1.1 miles 
northeast of Lee Valley, Lee Valley (T.V.A. 171-NW) Quadrangle. On U. S. 
Highway 25E, 4 mile north of Indian Creek, Howard Quarter (T.V.A. 162-NW) 
Quadrangle ; Nicely and Palmer’s store, 3 mile east of Kate, Maynardville (30’) 
Quadrangle. 
Pierce formation in Tennessee: At Murfreesboro. 
