Crinoids, Blastoids and Brachiopods. — Rowley. 3<)7 
Among the specimens from which the description was made 
out is quite a great deal of variation in outline and general 
appearance as well as size. Three different forms are figured. 
One specimen has a length twice as great as the width, another 
a greater width than length. The small specimen with a 
very convex base and proportionately broad ambulacra 
mimics a true IVntremites. Two others have the exact out- 
line of Pentremites conoideus in miniature. There i- greater 
range in outline and characters in this little blastoid than we 
have seen in other species. It may be compared witli G. pi- 
sum and G. exiguum. 
Collected from the Chouteau limestone, three miles east of Curry - 
ville, Mo. Types in the author's collection. 
Spirifera miuidula (nov. sp.). 
(Plate xiv, fig. 10. Ventral valve, natural size. Fig. 11. Cardinal 
view, natural size. Fig. 12. Outline, of cross sectioD, natural size. I 
Shell transversely elongate, the width being nearly three 
times the length. Plications on both valves few. simple* and 
not very distinct, about fourteen being all that can be 
counted to the valve. Mesial fold small, more elevated than 
the plications and with a slight central sulcus. Sinus narrow 
and rather shallow. Both the mesial fold and sinus without 
plications. A few indistinct lines of growth cross the ribs 
on both valves. Viewing the shell lengthwise of the cardinal 
area (fig. 12.) the outline or cross section is singularly 
rounded. Beak of the ventral valve incurved. Cardinal area 
occupies the entire width of the shell and is narrow and of 
almost uniform width. Foramen small, triangular. Length 
of type };], width L 6 ff , thickness r 6 g of an inch. 
This elegant little Spirifera comes from the Lower Burlington lime- 
stone at Louisiana, Mo. The collection contains two specimens. 
Spirifera aeieulifera (nov. sp.). 
(Plate xiv, fig. 13. Cardinal view, two diameters. Fig. 14. Ventral 
valve, two diameters.) 
Shell somewhat cyrt ina-l'orin, small, width a little greater 
than length. On the ventral valve there are about seven small 
butdistinct plications, either side of the sinus, which latter is 
well defined hut without plications. On the dorsal valve 
there are six costse either side of the mesial fold hut none on 
the fold itself, which is distinct and slightly flattened on top. 
