PLATE XXXVII. 



MODIOMORrHA ALTA. 

 Page 278. 

 See Plate 80. 

 F\g». 1, 2, 7-12, 15, 16. These fig-ures represent characteristic specimens of this species in its various 

 phases of growth. Fig. 15 is the type specimen descnbed by Mr. Conrad. 

 Hamilton group, ^hore of Seneca lake, N. Y. 

 Figs. 4-6 are doubtfully referred to this species, approaching H. mytiloideg in form. 



MODIOMORPHA .MVTILOIUES. 



Page 277. 



See Plate 38. 

 Fig. 3. A small left valve of this species. 



Hamilton group. Pratt's falls, N. Y. 



MODIOMORPHA AFF1NI8. 

 Page 284. 

 See Plate 35. 

 Figs. 13, 14. Right and cardinal views of the specimen described. 

 Hamilton group. Onondaga Co., N. Y. 



MOWOMOKPHA JIACILENTA. 



Page 280. 



See Plate 39. 



Fig. 17. The right side of a crushed 8i)ecimen. 



Hamilton group. From a boulder of shaU in Catherine township, Schuyler Co., N. Y. 



