NO. I2 PERMIAN BRACHIOPODS FROM OREGON—COOPER 35 
Localities —Pi10; S20, S67. 
Discussion.—This species is characterized by its subquadrate form, 
strong convexity, strongly reticulate visceral region and strong sulcus. 
This species is more like A. hessensis than it is like its associate in 
the Oregon fauna. It is more convex and longer than A. sulcatus 
and is differently ornamented. It differs from A. hessensis in being 
larger, somewhat more strongly ribbed, with a larger reticulate area 
and more convex profile. 
ANTIQUATONIA SULCATA Cooper, new species 
Plate 5C, figures 18-22 
Shell fairly large for the genus, wider than long with the hinge 
forming the widest part. Lateral margins gently rounded; anterior 
margin broadly rounded, emarginate medially. Slightly less than 
posterior half of the shell reticulate, the trail costate, the costae nar- 
rowly rounded and separated by spaces not quite equal to the costae 
in width, and 7 to 8 costae occupying a space of Io mm. on the front 
half. 
Profile of pedicle valve strongly convex with the greatest curvature 
slightly posterior to the middle; reticulate or visceral portion strongly 
convex with strongly curved beak which, however, protrudes slightly 
beyond the posterior margin. Umbonal region slightly convex but 
with steep slopes to the cardinal extremities. Sulcus originating 10 
to I2 mm. anterior to the beak as a narrow groove, deepening rapidly 
but not materially widening in its extent to the front margin. Flanks 
bounding sulcus strongly rounded with steep lateral slopes to the mar- 
gins; ears prominent, moderately extended, narrowly rounded in 
profile. Lateral slopes over ears marked by a low curving ridge bear- 
ing a row of spines; ridge variable in elevation and definition. 
Brachial valve forming with the pedicle valve a moderately deep 
visceral chamber ; visceral area nearly flat in profile but with a concave 
umbo and concave area in front of umbo extending for about 8 or 
Q mm. anterior to the beak where the concavity changes to a low and 
narrow fold with gently sloping sides that extend to the front mar- 
gin. Areas surrounding the sulcus on the visceral region slightly 
convex especially in the neighborhood of the cardinal extremities. 
Brachial valve geniculating about 20 mm. anterior to the beak strongly 
in the direction of the brachial valve. Geniculate area narrowly 
rounded in profile; trail very slightly convex in profile, steep; ears 
of brachial valve moderately long, narrowly rounded in profile, a 
narrow, curved groove anterior to the ear corresponding to the ridge 
on the slope of the pedicle valve. 
