PLATE LXXXIIl— Contiimed. 



Genus TREMATOSPIRA, Hall. 



Page 124. 



Trematospira Tennesseensis, sp. uov. 



FifTs 21-23. Dorsal, j>rofile and ventral views of the .shell ; showing the convexity of the valves and the 

 coarse plication. 



Lower Helderberg grou]). Ptrry aniiitij, Tennessee. 



Subgenus HOMCEOSPIRA, s.-gen. nov. 



Page ll>. 



See Pliitc .")(). 



HOMCEO.SPIRA APRINIFORMIS, Hall. 



Figs. 24, 2,^. Dorsal and profile views ; showing the contour and character of plication. 

 Niagara group. Cumberland, Maryland. 



Genus EUMETRIA, Hall. 



Page 115. 

 See Plate 5L 



EuMETRIA VeRNEUILIANA, Hilll. 



Figs. 26, 27. Dorsal and profile views of a large, sharply costate individual. 

 St. Louis limestone, l^pergen Hill, Indiana. 



Genus PTYCHOSPIRA, gen. nov. 



Page 112. 

 Set- Plate .'>(). 



Ptychospira sex-plicata, White uikI Whitiield. 



Fig. 28. The exterior of a pedicle-valve of the type specimen. 

 Kinderhook group. Burlington, Itnea. 



Genus ZYGOSPIRA, Hall. 



Page 151. 



See Plate 54. 



ZyGOSPIRA PUTILLA, S\). IIOV. 



Figs. 29, 30. Dorsal and ventral views of a typical examjile. 



Hudson River group. Pike county, Missouri. 



Genus RHYNCHOTREMA. Hall. 



Page 182. 

 See Plate 5G. 



Rhynchotrema c^pax, Coiinid. 



Fig. 31. Cai'dinal view of the pedicle-valve shown on plate 56, tig. 17 ; .showing the excavation of the 

 pedicle-pa,ssage and its opening through the substance of the shell. X 3. 

 Hudson River group. Iron Mid^/e, Wisconsin. 



Genus GLASSIA, Davidson. 



Page 1.^2. 

 GlASSIA RoMINGERI, tfj). uov. 



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 2. 



Trenton limestone. In a drift boulder, "near Ann Arbor, Michigan. 



