32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
N.M. 12532I1a,b, 125322, 125323b, 125324; unfigured paratypes, 
U.S.N.M. 125320a,b. , 
Localities —636; L8, L23; S12, S14, S30, S40, S43, S45, S46, 
S49, S87, S103, S106; U.O. 2201-2, 2202-2, 2202-3, 2202-5, 2202-6, 
2204-1, 2204-3. 
Discussion—This species is characterized by its large size and its 
surface covered by elongate, distant pustules or spine ridges. It is 
most suggestive of Productus tuberculatus Moeller but differs in 
having an obscure median sulcus on the pedicle valve rather than a 
distinct and fairly deep one as on the Russian species. Furthermore, 
the spine bases of the American species are more elongated than those 
of the Russian species and are somewhat more abundant. This species 
is fairly common in the Oregon Permian. 
Productus subhorridus Meek is an American form that may be 
related but it differs markedly in form, profile, and the arrangement 
of the spines. This stock of productoids appears in the early Permian, 
is common in the Leonard, and reaches a large size in the Word. 
KROTOVIA aff. K. BARENZI (Miloradovitch) 
Plate 10C, figures 12-17 
Krotovia barenzi MiLorapovitcH, Trans. Arctic Inst., vol. 37, p. 139, pl. 5, fig. 12, 
1935; Branson, Geol. Soc. Amer. Mem. 26, p. 378, 1948. 
Material poorly preserved and consisting of several pedicle valves ; 
small, length and width nearly equal, outline suboval ; lateral margins 
gently rounded, anterior margin broadly rounded; hinge slightly 
narrower than the maximum width which is near the middle. Lateral 
profile strongly convex; anterior and posterior profiles narrowly 
domed. Beak narrow and incurved, protruding beyond the posterior 
margin. Umbo swollen. Surface ornamented by distant growth var- 
ices and small closely crowded spines covering all parts of the pedicle 
valve. 
Measurements in mm.—Figured specimen, U.S.N.M. 125336b, 
length 16.2, width 15+, hinge width 12.9, surface measure 27.5; 
figured specimen, U.S.N.M. 125336a, length 13.2, width 11.6, hinge 
width ?, surface measure 22. 
Types.—Figured specimens, U.S.N.M. 125336a,b. 
Locality.—Stot. 
Discussion ——This species is characterized by its small size and 
elongate form. The specimens closely resemble those figured by 
Tschernyschew (1902, pl. 30, fig. 8). 
