NO. 12 PERMIAN BRACHIOPODS FROM OREGON—COOPER 21 
Class“PYGOCAULIN 
Suborder DALMANELLOIDEA Moore, 1952 
Superfamily DALMANELLACEA Schuchert and Cooper, 1931 
RHIPIDOMELLA sp. 1 
Plate 1F, figure 12 
This genus is represented by a single specimen, a small brachial 
valve having a length of 5.6 mm. and a width at the widest point, 
slightly anterior to the middle, of 5.4 mm. Anterior profile somewhat 
strongly convex and slightly narrowed in the median region. Lateral 
profile most convex in the umbonal region and becoming less convex 
anteriorly. Lateral margins broadly rounded ; anterior margin broadly 
rounded ; posterior margin somewhat narrowly rounded. Beak small, 
protruding slightly posterior to the posterior margin. Median region 
marked by a faint sulcus. Costellae narrowly rounded, about 4 to the 
millimeter at the front margin. 
Type.—Figured specimen, U.S.N.M. 125314. 
Locality.—S1o1. 
Discussion.—This is obviously a juvenile specimen and is thus 
difficult to relate to any of the known species from Russia or the 
United States. 
Suborder STROPHOMENOIDEA Maillieux, 1932 
Superfamily OrTHOTETACEA Williams, 1956 
Family ORTHOTETIDAE MacEwan, 1939 
DERBYIA sp. 1 
A single imperfect brachial valve is the only representative of the 
large Derbyias usually so common in the Permian. It is 48 mm. long 
and more than 60 mm. wide. The lateral profile has moderate con- 
vexity. These measurements thus indicate a large species but no 
specific characters of significance can be determined. 
Type.—Described specimen, U.S.N.M. 125532. 
Localities —St1o1, S103. 
DERBYIA sp. 2 
Plate 1B, figures 4-7 
About medium size for the genus, wider than long, semiconical in 
outline. Sides rounded; anterior margin broadly rounded. Surface 
costellate, costellae numbering 2 to 3 to the millimeter at the front 
margin. 
