PLATE XLVII—Continued. 
Fig. 
Pig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Pig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Seminula subtilita, Hall. 
17. A view of the hinge-plate; showing its excavate upper face, subquadrate outline, striated pos¬ 
terior extensions and minute visceral foramen. X 5. 
(?) Chester limestone. Caldwell county, Kentuchy. 
18. The hinge-plate of another specimen; showing some differences in outline and surface. The 
position of the visceral foramen is occupied by a minute lobe. X 5. 
Coal Measures. Manhattan, Kansas. 
19. A dorsal view of an orbicular and faintly lobed form. 
Coal Measures. Coppe7’S Creek, Iowa. 
20. A large specimen, very broad in the pallial region and strongly lobed on the anterior margin. 
(?) Chester limestone. Chester, Illinois. 
21. A large individual with greatest width more posterior, strong anterior lobe, and shai’p concentric 
lines. 
Coal Measures. Charito7i county, Missouri. 
23. An extremely trilobed shell with the greatest width near the anterior margin. The fine radiating 
lines upon the shell are seen only where the epidermal layer has been abraded. 
Coal Measures. Winterset, Iowa. 
23. An extremely elongate form, broadly lobed on the anterior margin. 
Coal Measures. Miami county, Kansas. 
24. The interior of the pedicle-valve of an old and much thickened shell; showing the deep pedicle- 
cavity and the broad, obscurely-defined muscular area. 
Coal Measures. Kansas City, Missow'i. 
26. An internal cast of the spiral cones, viewed from the dorsal side. 
Coal Measures. Locality ? 
26. A preparation of the brachidium, a portion of the spirals being cut away to expose the loop. The 
figure shows the furcated anterior extremity of the saddle, the position and extent of the 
accessory lamellte and the fimbriation of the anterior portion of the first few lamellse of the 
coils. X 3. (c.) 
Coal Measures. Winterset, Iowa. 
27. A dorsal view of an internal cast slightly restored at the beak ; showing the adductor scars and 
vascular impressions. 
28. The opposite side of the same specimen; showing the adductor scars while the diductors are 
not clearly defined. This is a cast in iron-stone and its source is undetermined, but it is prob¬ 
ably from the 
Coal Measures. Ohio. 
29. The interior of a very elongate and much thickened pedicle-valve ; showing the adductor and 
diductor scars deeply excavated in the shell substance. X 2. 
Coal Measures. Near Kansas City, Missoun. 
30. Antei'ior marginal view of a large and old shell with greatly thickened valves. This shell is of 
the form represented in figure 22, but is much older and is somewhat unsymmetrical, having 
suffered injury at the right of the median fold. 
31. A preparation of the brachidium, the upper half of the spiral cones having been removed. This 
figure has been drawn from a transparency, and the saddle of the loop appears very long. 
Through an error in lithography the lateral branches of the loop have been disconnected from 
the primary lamellse. X 2. (c.) 
Coal Measures. Winterset, Iowa. 
Seminula Dawsoni, sp. nov. (= Athyris subtilita, Duvidsori). 
32. A view of the brachidium naturally jireserved by incrustation and exposed by the removal of a 
portion of the pedicle-valve; showing the form of the cones and the position of the accessory 
lamellse. X 2. 
33. A dorsal view of the exterior of conjoined valves. X 2. 
34. A profile view of the same specimen. X 2. 
Coal Measures. Windsor, Nova Scotia. ' 
Athyris (Seminula ?) sp. ? 
35. A transparency viewed fi’om the ventral side ; showing the attachment of the crura to the primary 
lamellse, a portion of the loop and the accessory lamellje and the fimbriated coils of the spirals. 
The specimen is interesting in showing the asymmetry of the coils, the cone on the left side 
possessing eleven volutions, that on the right but eight. The filling of the shell is transparent 
calcite and the brachidium has been rexdaced by red hematite. X 3. (c.) 
Coal Measures ? Ohio. 
