Puenax puenus, Sowerby. 
Figs. 20, 21, 22, 23. Dorsal, ventral, front and profile views of an internal 
cast; showing the contour of the shell and the form of the muscular 
impressions. 
Chemung group. High Point, Naples, N. Y. 
Puenax attus, Calvin. 
Figs. 24, 25. Profile and front views of an example with highly-elevated 
median fold. 
Middle Devonian. Hackberry Grove, Iowa. 
RHYNCHOPORA, Kine. 
Page 832. 
RuayNncHopora PustuLosa, White. 
Figs. 26, 27, 28, 29. Dorsal, ventral, profile and front views of a normal 
example. 
Burlington limestone. Burlington, Iowa. 
EATONIA, Hatt. 
Page 829. 
: Hatonia PEcULIARIS, Conrad. 
Fig. 30. The interior of a brachial valve; showing the extent of the cardinal 
process. 
Oriskany sandstone. Cumberland, Maryland. 
Fig. 31. An internal cast of the pedicle-valve; showing the impressions of the 
adductor and diductor scars and the vascular sinuses. 2. 
Fig. 32. The interior of a brachial valve viewed in profile from the front mar- 
gin; showing the elevation of the cardinal process, its lobation and 
the elevation of the crura. 
Oriskany sandstone. Albany county, N. Y. 
Fig. 33, Front view of a specimen; showing the development of median fold 
and sinus and the dentate margins. 
Lower Helderberg group. The Helderbergs, N. Y. 
Fig. 34. The interior of a pedicle-valve; showing the open delthyrium, mar- 
ginal teeth, large diductor scars, small adductors with strongly ele- 
vated posterior walls, the dentate shell margins and the lingulate 
extension of the median sinus. 
Oriskany sandstone. Cumberland, Maryland. 
EaTONIA SINGULARIS, Vanuxem. 
Fig. 35. Ventral view of a large shell. 
Figs. 36, 37. Front and profile views of another example. 
Lower Helderberg group. Albany county, N. Y. 
EaTONIA MEDIALIS, Vanuxem. 
Figs. 38, 40. Dorsal and ventral views of a normal example. 
Fig. 39, An internal cast of an old pedicle-valve with strong muscular scars. 
Lower Helderberg group. Albany county, N. Y. 
125 245 
