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SS ———— 
NO. I2 PERMIAN BRACHIOPODS FROM OREGON—-COOPER 65 
Localities —Pi1; S41, S5o. 
Discussion.—This species is unique in known American faunas. 
Most of the small terebratuloid species referred to Notothyris have 
no hinge plate and are referable to other genera. None of the species 
referred to Notothyris has the long median process on the loop as 
seen in Rostranteris. The Oregon species referred here to Rostran- 
teris is quite clearly an adult shell and is therefore congeneric with 
Gemmellaro’s genus. It does not, however, resemble any of the 
Sicilian species. The Oregon form is reminiscent of Rhynchonella 
keyserlingi Moeller, 1862, which is referred by Tschernyschew to 
the genus Pugnax. The original of this species, figured by Tscherny- 
schew (1902, pl. 21, fig. 18), shows a small but extremely thick 
shell similar to R. merrianu, new species. The Oregon species differs 
from the Russian one in stronger and more elevated costae, a well- 
defined fold on the pedicle valve made up of 2 costae with a wide 
sulcus between. The brachial sulcus is occupied by a single costa 
quite unlike the Russian species. 
ROSTRANTERIS SULCATUM Cooper, new species 
Plate 12A, figures I-11 
Shell small, longitudinally ovoid in outline, unequally biconvex in 
profile; sides convex; anterior narrowly rounded. Surface semi- 
costate, shell substance punctate. 
Pedicle valve deep, strongly and evenly convex in lateral profile, 
with the greatest convexity at about the middle. Beak strongly in- 
curved; umbonal region narrowly convex. Pedicle valve marked by 
a broad and shallow sulcus defined by 2 prominent costae that orig- 
inate near the middle of the valve and extend to the front margin, 
heightening and strengthening anteriorly. The sulcus is occupied by 
a low costa beginning anterior to the middle and strengthening in 
an anterior direction. Sulcus produced into a long, tapering tongue. 
Flanks convex, steeply sloping to the margins and provided with a 
single obscure costa. 
Brachial valve shallower than the pedicle valve, slightly convex in 
lateral profile, fairly strongly convex in anterior profile. Umbo nar- 
rowly swollen ; median area slightly swollen; fold originating slightly 
anterior to the middle short, narrow, low, and marked in the middle 
by a narrow sulcus corresponding to the median costa that occupies 
the sulcus of the ventral valve. Flanks steep-sided and convex, 
marked anteriorly by a single obscure costa. 
