PLATE LI—Continued. 
PaLxEONEILO CONSTIUCTA. 
Page 333. 
See Plate 48. 
Fig 1 . 17. A left valve, enlarged. 
Portage group. Near Portland Harbor, N. ¥■ 
Nucula lamellata. 
Page 320. 
See Plates 45, 915. 
Fig. 18. A right valve, enlarged. 
Hamilton group. Shore of Cayuga lake, N. Y. 
Fig. 19. A specimen retaining the two valves in co'njtnictiijn, enlarged. 
Hamilton group. Shore of Cayuga lake, N. Y. 
Fig. 20. A left valve, enlarged. 
Fig. 21. A right valve, enlarged. 
Hamilton group. Shore of Cayuga lake, N. Y. 
iTg 
mo'lt urtol 
tfollitnr.ll 
in rn; 'to Tv/l 
nnliimnH 
mi unia A A 
nifrrao :A .6 
by flaf A .01 
Ptychodesma Kaappianum. 
Page'BaL 
Figs. 22, 23. Cardinal views of two specimens. 
Figs. 24-26. Left and two right valves showing some variation in form. 
Fig - . 27. An enlargement of one side of the ligamental area: . 
Hamilton group. Near Louisville, Ky., and Cla.rke County, Indiana. 
D YST ACTE L L A TELIA XIF 01 l MIS. 
Page 513. 
Figs. 28, 29. Lateral and cardinal views of a small specimen. 
Corniferous limestone. Canada West. 
Fig. 30. xV cast of the interior preserving the remain's of some concentric undulations. The specimen is 
imperfect, and is completed in the figure by comparison with other individuals. 
Corniferous limestone. Canada West. 
Fig. 31. A cast of the interior of a specimen. 
Corniferous limestone. Western New York. 
Dystactella subnasuta. 
Page 5P2.‘ ' 
Sek Plate' 95. 
Fig. 32. The left side of a specimen showing muscular scar and pallial line. 
Fig. 33. The right side of a specimen preserving the concentric striae. 
Corniferous limestone. Near Louisville, Ky. 
