PLATE LXXXUI—Continued. 
Genus TREMATOSPIRA, Hall. 
Page 124. 
Trematospira Tennesseensis, sp. nov. 
Figs 21-23. Dofsal, protile and ventral views of the shell; showing the convexity of the valves and the 
coarse plication. 
Lower Helderberg group. Perry county, Tennessee. 
Subgenus H0MG50SPIRA, s.-gen. nov. 
Page 112. 
See Plate .50. 
HoMCEOSPIRA APRINIFORMIS, Hall. 
Figs. 24, 25. Dorsal and jirotile views; showing the contour and character of plication. 
Niagara group. Cmnherland, Maryland. 
Genus EUMETRIA, Hall. 
Page 115. 
See Plate 51. 
Eumetria Verneuiliana, Hall. 
Figs. 26, 27. Dorsal and profile views of a large, sharply costate individual. 
St. Louis limestone. Sjpergen Hill, Indiana. 
Genus PTYCHOSPIRA, gen. nov. 
Page 112. 
See Plate 50. 
Ptychospira sex-plicata, White and Whitfield. 
Fig. 28. The exterior of a pedicle-valve of the type specimen. 
Kinderhook group. Burlington, Iowa. 
Genus ZYGOSPIRA, Hall. 
Page 154. 
See Plate 54. 
Zygospira putilla, sp. nov. 
Figs. 29, 30. Dorsal and ventral views of a typical example. 
Hudson River group. Pike county, Missoun. 
Genus RHYNCHOTREMA, Hall. 
Page 182. 
See Plate 56. 
Rhynchothema capax, Conrad. 
Fig. 31. Cardinal view of the pedicle-valve shown on plate 56, fig. 17 ; showing the excavation of the 
pedicle-passage and its opening through the substance of the shell. X 3. 
Hudson Rivei' group. Iron liid.ge, WisconMn. 
Genus GLASSIA, Davidson. 
Page 1.52. 
Glassia Romingeri, sp. nov. 
Fig. 32. A preparation .showing the introverted coils and the direction of the loop. X 3. 
Figs. 33-35. Dorsal, profile and venti’al views of a specimen, showing the smooth exterior and bilobed 
anterior margins of the valves. X 
Trenton limestone. In a drift boulder, near Ann Arbai’, Michigan. 
