262 The American Geologist. May, i9oo 
Valves ne^uiy cquall)' convex. Hinoc line shorter than 
the greatest width of the shell, niakin<^ the valves subcircu- 
lar. Surface with rounded plications, four or five either side 
of the sinus and mesial fold. Pedicel valve more convex 
than the brachial. Beak arcuate, over a small ill defined, 
triangular cardinal area, Mesial fold and sinus distinctly 
defined and without plications. Surface ornamented with 
diagonal rows of granules. The specimen figured is medi- 
um in size and without apparent lines of growth. A larger 
individual in the collection, however, is crossed by two or 
three concentric stride. 
The collection contains five specimens, collected from 
the limy cherts of the Lower Burlington limestone at Lou- 
isiana, Mo. 
Specific name in honor of Mr. Charles Schuchert of the 
National Museum, Washington, D. C. 
Spirifer louisianensis (nov. sp.). 
Plate V, Figs. i8, iq. 20. Dorsal, ventral, and cardinal views, natu- 
ral size, of an above medium example. 
■ Fig. 64. Enlargement of the surface to show the fine, numerous, 
concentric lines of growth. 
Shell semi-circu>ar, hinge line equal to the greatest width 
of the shell. Cardinal extrem.ities obtuse. Area rather 
high, triangular. Sixteen to twent}' rounded plications, 
crossed near the front by three or more rather strong lines 
of growth to each valve. Whole surface ornamented by 
fine, crowded, concentric lines or striae. Pedicel valve more 
convex than brachial; beak slightly incurved; sinus fairly 
well defined with obscure plications. Mesial fold not well 
defined, plicated. The collection contains ten examples of 
this Spirifer, all collected from the limy cherts of the Lower 
Burlington limestone at Louisiana, Mo. 
Ambocoelia levicula (nov. s}).). 
Plate V, Figs. 12, 13, 14. Dorsal, ventral and profile views of a 
large specimen, natural size. 
Pedicel valve gibbous. Brachial valve flat or slightl)^ 
convex with or without a faint median depression. Beak of 
the pedicel valve comparatively strong, incurved. Umbo 
