PLATE LX—Coutinued. 
PuoNAX MissouriENS is, Slnimai'd. 
Figs. 33, 34. Dorsal and pi-ofile views of an average example : showing the lineate striation of the surface. 
Choteau limestone. Pike county, Missouri. 
Liorhynchus (?) Boonensis, Shuinard. 
Fig. 35. Cardinal view of the hinge-plate ; showing its .median division and the elevation of the crura. 
X 3. 
Choteau limestone. Cooper co^mty, Missouri. 
PuGNAX Greenianus, Uliicli. 
Figs. 36--38. Front, profile and dorsal views of an internal cast of an average individual; showing the 
smooth lateral slopes and faint plication of fold and sinus. 
Keokuk group. New Albany, Indiana. 
PuGNAX Uta, Mavcoii. 
Figs. 39-41. Dorsal, profile and front views of an average adult shell. 
Fig. 42. The interior umbonal portion of the brachial valve ; showing the broad hinge-plate and narrow 
median incision. X 3. 
Coal Measures. Manhattan, Kansas. 
PuGNAX EXPLANATUS, McChesiiey. 
Figs. 43-45. Front, dorsal and profile views, drawn from a sulphur cast of the original specimen. 
Kaskaskia limestone. Illinois. 
PuGNAX, Sp. ? 
Figs. 46-48. Profile, front and dorsal views of an undetermined internal cast. The shell has some points 
of similarity to the Rhynchonella Illinoisensis, Meek and Worthen. 
Coal Measures. Qraham county, Texas. 
Genus HYPOTHYEIS, King. 
Page 19,5. 
Hypothyris venustula, Hall (= Riiy'nohonella cuboides, Sovverb}). 
Figs. 49, 50, 52. Cardinal, frontal and profile views of a typical specimen ; showing the subcuboidal form, 
low median fold and broad, deep median sinus. 
Fig. 51. Front view of an internal cast with fewer plications, and showing the branches of the vascular 
trunks on the sinus. 
Figs. 53, 54. Internal casts of pedicle-valves ; showing the muscular impression, and some variation in the 
form of the vascular sinuses. 
Fig. 55. An internal cast of the pedicle-valve, enlarged to show the system of vascular sinuses. X 2. 
Tully limestone. Ovid, N. Y. * 
