Figs. 18, 15. Profile and cardinal views of a large entire individual; showing 
the robust form of the shell, its subquadrate transverse section, ser- 
rate margins and broad, somewhat concave cardinal slopes. The 
abrupt marginal extensions of the cardinal slopes of the pedicle- 
valve, fitting into corresponding excavations of the brachial valve, 
are the thickened teeth cemented to the walls of the valve through 
out their entire extent and, at their summits only, fitted into the 
shallow sockets of the opposite valve. 
Oriskany sandstone. Cumberland, Maryland. 
LIORHYNCHUS, Hatt. 
Page 827. 
LiokHYNcHUsS LimiTARis, Hall. 
Figs. 16, 17. Ventral and front views of a large specimen. 
Marcellus shales (Stafford limestone). Avon, N. Y. 
Lioruyncuus Laura, Billings. 
Fig. 18. Dorsal view of a rather elongate shell. 
Figs. 19, 20. Two views of the hinge-plate and crura. X 4, 
Hamilton group. Thedford, Ontario. 
LiokHYNCHUS mMESACOsTALIS, Hall. 
Fig. 21. An internal cast of the brachial valve; showing the extent of the 
median septum, the elongate muscular scars and the absence of 
plications on the lateral slopes. 
Chemung group. Tompkins county, N. Y. 
LioRHYNCHUS QUADRICOSTATUS, Vanuxem. 
Fig. 22, The exterior of a crushed and somewhat distorted pedicle-valve ; 
showing the character of the plication. 
Genesee shales. Western New York. 
Liorayncuus Newsereryi, Hall. 
Fig. 23, An internal cast of the brachial valve ; showing its fine and complete 
plication. 
Upper Devonian. Kelloggsville, Ohio. 
LiokHYNCHUS ROBUSTUS, Hall. 
Fig. 24. Ventral view of an internal cast; showing the muscular scars, and 
the vascular sinuses radiating from the impressions left by an umbo- 
nal testaceous callosity. 
Chemung group. Steuben county, N. Y. 
243 
