770 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
the road, 0.2 mile east of Strasburg; about 4 mile south of Strasburg Junction; 
ravine at switch just east of Strasburg Junction; all in Strasburg (15’) Quad- 
rangle. Collier Creek, $ mile north of the junction of Virginia County Highways 
251 and 612, about 6 miles west-southwest of Lexington, Rockbridge County. 
Shippensburg formation (lower 50 feet above New Market limestone) in 
Pennsylvania: In the field just north of the east end of the railroad cut 2 miles 
southwest of Marion Station, Chambersburg (15’) Quadrangle. 
Edinburg formation (Liberty Hall facies) in Virginia: Cut at the crossing 
of U. S. Highway 50 over Opequan Creek, southeast of Winchester, Winchester 
(15’) Quadrangle. 
Discussion.—This species, although small in size, is larger than B. immatura, 
B. matutina, or B. siphonata. It is really intermediate between these and B. la- 
mellosa. It is not so strongly umbonate as the latter and is generally not so 
strongly or so completely lamellose as the Oranda species. It is much smaller 
in size than either B. buttsi or B. superba. 
BIMURIA SIPHONATA Cooper, new species 
Plate 210, G, figures 17-24 
Shell small, transversely semielliptical, with the hinge equal to or slightly less 
than the greatest width; posterolateral extremity somewhat rounded ; sides gently 
rounded, somewhat oblique; anterior margin broadly rounded; posterior half to 
three-quarters usually smooth, anterior half to quarter often with thin concen- 
tric lamellae. 
Pedicle valve strongly and fairly evenly convex in lateral profile, the umbo 
forming the most rounded part; anterior profile forming a strongly convex, 
broad arch with evenly and moderately steeply sloping sides. Umbo swollen ; 
median region and sides strongly inflated giving the entire valve a fairly even 
convexity ; beak provided with a narrow siphon projecting directly posteriorly 
or inclined somewhat toward the pedicle valve and narrowing distally to form 
a tiny foramen; delthyrium open; muscle impressions too lightly impressed to 
be discernible or individualized. 
Brachial valve deeply and broadly concave, sharing the even convexity of the 
pedicle valve ; interarea with rudimentary chilidial plates and a small transverse, 
flat plate at the apex. Cardinal process not formed; brachial processes slender, 
extending along edge of palintrope ; median septum short, highest at point where 
lateral septa originate a short distance anterior to the apex; lateral septa low, 
moderately divergent and extending onto anterior slope; adductor scars located 
outside the septa and forming fimbriated lobe which is divided unevenly by a 
low, oblique ridge. 
Measurements in mm.— 
Length 
Brachial Mid- Hinge Thick- of 
Length length width width ness Height siphon 
BIOIGtV Es aS acs noes 2.0 1.9 4.4 4.4 ? 0.9 0.25 
Paratype (117470d).. 2.6 2.0 5.0 5.4 ? 1.5 0.40 
