New Brachiopoda.— Winchell and Sehuehert. 289 
lateral slopes rapid and slightly concave; greatest elevation about 
mid-length. Cardinal area strongly elevated, slightly concave, 
somewhat wider than that of the other valve; delthyrium about as 
wide as long, with a small deltidium in the posterior portion, and 
more or less occupied by the cardinal process and deltidium of the 
other valve. Teeth small, supported by strong dental lamellee. 
Diductor muscle pits deep, short, strongly diverging and separated 
posteriorly by a small septum. 
Brachial (dorsal) valve concave and closely following the curva- 
ture of the other valve. Cardinal area wide, flat, retrorse; del- 
thyrium with a large, simple cardinal process more or less covered 
by a deltidium which is usually imperfect medially. Crural 
processes short and widely divergent. Adductor muscle sears 
broadly triangular in outline, lobate, with the outer margin 
strongly elevated. 
The convexity of its valves, and the interior characters of the 
brachial valve will distinguish at once this species from P. sericea 
Sowerby and P, decipiens Billings. Plate xxxut, figs. 13-17, 
Plate xxx1, figs. 15-17. 
Formation und locality. Galena limestone four miles south of Cannon 
Falls, and at Mantorville, Minnesota. 
Orthis meedsi. 
Shell of medium size, suborbicular, in outline; biconvex; an- 
terior margin broadly deflected dorsally; hinge-line about one- 
fourth shorter than the greatest width; surface marked by strongly 
elevated, sharply rounded strizw, from forty-five to seventy on 
each valve along the anterior margin, crossed by numerous thread- 
like lines of growth; striz arranged in bundles of two or three, 
those of the pedicle valve bifureating, while on the brachial valve 
an increase takes place by interpolation. |Kxfoliated specimens 
show two or three rows of small black spots terminating on the 
striew, which may represent perforations in the shell substance. 
Pedicle (ventral) valve slightly convex, with a broad shallow 
inus; cardinal area of moderate width; slightly concave, elevated 
beyond, or depressed below that of the brachial valve; delthyrium 
small, triangular; beak slightly incurved. Interior characters of 
the valve are like O. pectine//a but less sharply defined. 
Brachial valve strongly convex centrally, with the lateral post- 
erior areas somewhat concave; cardinal area very narrow, slightly 
