NO. 12 PERMIAN BRACHIOPODS FROM OREGON—COOPER 45 
visceral disk and the long trail. The interior is imperfectly known 
because none of the Oregon species shows the marginal ridges, but 
one specimen, U.S.N.M. 125334, does show the cardinal process and 
this agrees with the interior of Alexenia? parvispinosa Stehli, the 
only described Permian species like the Oregon one. 
Alexenia? occidentalis differs from the west Texas species in having 
a larger size, longer trail, less transverse outline, and more concave 
brachial valve. The visceral disk region of a specimen of A.? parvi- 
spinosa is gently but definitely swollen to form a slightly convex area. 
The spines of the Texas species are fine and numerous but indications 
from the few spine bases seen on A.? occidentalis suggest much 
stronger spines. This would be in agreement with the larger size 
of the Oregon species. 
Shells similar to the Permian Alexenia? are common in the Penn- 
sylvanian and occur fairly frequently in the Wolfcamp and Leonard 
formations of the Glass Mountains. None of these, except Stehli’s 
species, appears to have been named. 
ALEXENIA? SUBQUADRATA Cooper, new species 
Plate 2A, figures 1-4 
Shell small, slightly wider than long; lateral margins gently 
rounded; anterior margin gently rounded; anterolateral extremities 
moderately rounded; posterior half fairly strongly reticulated; an- 
terior half costellate ; costellae subequal, separated by spaces narrower 
than the costellae, numbering about 6 in 5 mm. at the front margin. 
Pedicle valve with lateral profile moderately convex and with the 
geniculation at about the middle and forming an angle of 90°. Pos- 
terior half somewhat less convex than the anterior half or trail. Beak 
narrow, incurved, scarcely protruding beyond the hinge line. Umbo 
narrowly and strongly swollen and with precipitous slopes to the ears. 
Sulcus originating about 12 mm. anterior to the beak, narrow and 
shallow but extending to the anterior margin and forming a broad V 
in profile. Flanks bordering sulcus moderately broad and moderately 
swollen and with steep slopes to the margins. Ears small. Spines 
concentrated on lateral slopes, scattered on trail. 
Measurements in mm.—Holotype, length 22.1, width at middle 
26.1, width at ears 26.0, surface length 40.0, height 13.8. 
Type.—Holotype, U.S.N.M. 125328. 
Localities —L8; S106. 
Discussion.—This species is characterized by its subquadrate form, 
deep sulcus, and strong convexity. It differs from A.? occidentalis, 
