I'LATi;: LIX— Coiiltiiucd. 



GUAMMYSIA CONSTRICTA. 



Pago S77. 



See Plate 78. 



Vig. 13. The rig^ht fiiile of a small individual i-etaining the i)roi)er fonn of the shell. 



Pig. 14. The right valve of another individual, the anterior end shortened by compression in an ubliqu6 

 ilii-ection. 



Hamilt4>n jn"<'"P- Sliore of Seiieea lake, N. Y. 

 V\g. 15. A left valve, the anterior end shortened by compi-ession. 

 ¥\g. 16. A right valve retaining the nonnal form. 



Hamilton group. Schoharie Co., N. T. f • 



Fig. 17. A small left valve somewhat shortened anteriorly by compi-ession, the surface presemng a few ot 

 the radiating strite, enlarged to two diametei-s. 

 Hamilton grouj). IjudUnpville., N. Y. 

 Fig. 18. A cai-dinal view of a specimen of ordinary dimensions. 



Hamilton group. Shore of Canandaigna lake, N. Y. 

 Fig. 19. The right side of a specimen i-etaining both valves, the anterior end greatly shoi-tened by com- 

 presedon, the surface preserving the radiating stiise, enlarged to two diameters. 

 ' ' Hamilton group. Schoharie Co., N. Y. 

 Fig. 20. An enlargement of the surface showing the pustulose character, from the specimen fig. 18 



Grammysia obsoleta. 



Page 366. 

 Figs. 21-23. Left side, anterior and cardinal views of a specimen which is vertically compressed. 



Hamilton group. Oazeniovia, N. Y. 

 Fig. 24. The interior of a left valve showing the cardinal area and elevation of &e umbo. 



Hamilton group. Svholuirie Co., N. Y, 

 Fig. 25 A specimen retaining the two valves in conjunction, each one of which is somewhat nan-owed by 



compression. 

 Fig. 26. A left valve jireserving nearly the noimaJ propoi-tions. , . 



Hamilton gi-oup. Pratt'.i falU, N. Y. .I«h1m /rimi ciili'riiK 

 Fig. 27. A left valve of a sjx-cimen somewhat > compressed and showing thft chaj-acteristic fold and sinus 

 np<m the anterior end of the valve. ii-.iiilKin'. A .L'l .yyi 



Hamilton group. Schoharie Co., N. Y. 



