New Missouri Fossils. — Roivlcy. 263 
very much elevated. Area not well defined. Cardinal ex- 
tremities rounded. Median sinus as a line-like depression 
that widens a little toward the- front. Surface apparently 
smooth. 
The collection contains a dozen or more specimens from 
the limy cherts of the Lower Burlington limestone. The 
specimens \'ar\" in size from very small forms to those as 
large as the figure. 
Nucleospira obesa (nov. sp.). 
Plate y. Figs. 38, 30, 40. Dorsal, ventral and profile views of a me- 
dium sized specimen. 
Shell subspheroidal, nearl)' circular in outline; the length 
being usually a little greater than the breadth. Brachial 
valve convex and crossed b}- lines of growth or smooth. 
Pedicel valve more convex with beak incurved. Area small, 
hidden by the incurved beak of the pedicel valve. Neither 
mesial fold nor sinus de\'eloped. Surface apparenth' smooth 
and without striae. To the conditions of prescr\-ation the 
apparent absence of the hair-like spines, characteristic of 
the genus is due. The author's collection contains half a 
dozen specimens collected from the soft, white cherts of the 
Lower Burlington limestone at Louisiana, Mo. 
Seminula bisinuata (nov. sp.). 
Plate X, Figs. 21, 22, 23,24. Dorsal, ventral and profile views of a 
large specimen, natural size. 
Shell pentagonal. Brachial valve with a median eleva- 
tion or fold, bilobed in the largest specimen by a line-like 
furrow. Either side of the median fold is a rather strong- 
depression, widening toward the front and giving this valve 
a trilobed appearance. 
Pedicel valve with a sinus that is wide and deep at the 
front and slightly elevated along the bottom b\- a poorl>' 
defined rounded rib. 
Beak of the pedicel valve rather long, incurved, and per- 
forated at the extremity by a small hole. 
Strong lines of growth cross some of the specimens. The 
collection contains 11 specimens, collected from the soft 
chert nodules of the Lower Burlington limestone at Louis- 
iana, Mo. 
