NO. 12 PERMIAN BRACHIOPODS FROM OREGON-——COOPER 43 
MARGINIFERA? MULTICOSTELLATA Cooper, new species 
Plate 5B, figures 14-17 
Shell of about medium size for the genus, known from the ped- 
icle valve only. Subrectangular in outline and the visceral region 
occupying nearly half the surface length. Visceral region coarsely 
reticulated; trail strongly and evenly costellated. Costellae num- 
bering about 7 in 5 mm. at the front margin. Sulcus originating 
about 5 mm. anterior to the beak, broad and shallow from point 
of origin to front margin. Beak small, umbo moderately swollen. 
Visceral region moderately convex in lateral profile; trail more 
convex than the visceral region in lateral profile. Flanks bounding 
sulcus gently swollen and with steep lateral slopes. 
Measurements in mm.—Holotype, surface length 18.0, length 
9.9, hinge width 15.6, midwidth 12.8, height 6.2. 
Types.—Holotype, U.S.N.M. 125365. 
Locality.— S46. 
Discussion.—This species is characterized by its broad but shal- 
low sulcus, short trail, wide hinge, and strong costellae. It is most 
like Marginifera profundosulcata, new species, but differs from it 
in having a shallower sulcus, finer costellae, and rounded flanks. 
The interior, however, is unknown; consequently, it could not be 
assigned to the new genus Probolionia. 
MARGINIFERA? PROFUNDOSULCATA Cooper, new species 
Plate 6B, figures 18-21 
Shell of about usual size for the genus, subrectangular in out- 
line; lateral margins sloping toward the valve middle; anterior 
margin medially emarginate; ears prominent, subalate. Visceral 
disk region obscurely reticulate; trail marked by low, broadly 
rounded costellae. 
Pedicle valve with visceral region about 8 mm. long and trail 
about 10 mm. long; visceral region nearly flat in lateral profile; 
umbo narrowly swollen; umbonal slopes gentle. Trail strongly 
geniculated from visceral region, gently convex in lateral profile. 
Sulcus originating about 3 mm. anterior to the beak, narrow and 
deep, widening and deepening anteriorly to form a deep U-shaped 
trough. Flanks bounding sulcus narrowly rounded and with long, 
precipitous lateral slopes. 
Brachial valve deeply concave; umbo forming a deep trough; 
median fold strong, originating about 4 mm. anterior to the beak. 
No diaphragm. 
