PLATE LXXXV— Continue^. 



I'l ■vi'iioi-rr.iMA BeeCHEKI. 



Pig. 21. An entire left valve showing its gibbon lateform. 



22. A right valve of this 



i ihemung group. 



Ptychopteria lata. 



Page 1 1".. 

 Pig. 23. An entire left valve. 

 Pig. 24. A larger left valve. 



Pig _'.". A right valve showing its comparatively strong alar fold. 

 ( Ihemung group. I Va ■ i, Pa. 



PtYCHOFTERI \ A.LAT \. 

 Page 189. 

 See Plate 23. 

 Pig. 26. The posterior half of ;i left valve, showing the subangnlar posterior slop,-. 



. .V. }". 



Ptychoptbria Eucrate. 



Page 133 

 See Plate 23. 

 Pig. .'7. A left valve of this species. 



Fig. 28. A small left valve. 



i Ihemung group. Panama, .V. Y. 



Ptychopteria Galene. 



i e 14-2. 

 Pig. 29. A left valve Battened by pressure. 



30. A smaller left v alve preserv ing the mil proportions of th 



Kig. 31. The right valve of a specimen preserving both valves. 

 Chemung group. Wat ■ n, Pa. 



Pttchopteria Thalia. 



■ 14S 



Pig. ::•_•. A small right valve. 



Pig. :i:i. A medium si/i-il left valve showing Mi.- short gibbous form of the shell. 

 Chemung group. Alleghany Springs, Warren Co., 



I'l TCHOPTBRIA TRIG* »NALIS. 

 no 

 Pig. 34. \ small left valve showing the form ami characters of the species. 

 Pig 35. A large imperfect left valve. 



Chemung group. Panama, N. )'. 



PT1 'in in ERIA Vam \kmi. 

 Pagi 

 16. A portion of ft valve, showing the peculiar form of the body ami the surface characters, 



( Ihem jP 



I'll CHOPTER] \ LOBATA. 

 Page 

 Pig. ST. A left valve showing th.' short form <■( tin- valve ami the str.mD alar plica! 

 Chemung group. Warren, I 



I'l rCHOPTER] \ PERLATA. 

 Page 1 17. 

 Pig, ::s. a right valve of this species. 



39. A left valve showing the form and surface marki 

 Chemung group. 1 1 ' 



