PLATE XXXI. 

 .\h riLARGA (Plethomytilus) oviformis. 



Page 



See Plate 87. 



Fig. 1. A left valve ofa young shell of elongate form. 



I [amilton group. ' ■ ■ ■ lake, X. Y. 



Pig. 2. A lefl \ ah e of the ordinarj size, showing the striate I hinge-area and tin posterior teeth on 



wing which are not sufficiently marked in the lithography. 



Hamilton group. Cayuga lake, 3F. Y. 

 Fig. .'!. A right valve showing the strong ligamental area. 

 Fig. 4. A i longate form with attenuate beak. 



Hamilton group. e, Livingston < ■>.. X. Y. 



Fig. 5. The anterior side of ;i compressed specimen preserving the valves in contact at the hinge, bul 

 widelj parted below. 



Hamilton group. Gfeneseo, I. . X. Y. 



Fig. 6. A large right valve widened below bj compression. 



Hamilton group. Seneca lake, iV. 1". 



Fig. 7. A cast ofa small elongate right valve. The beak has I n removed to show the ligamental area : 



tin- tin oblique lateral t < - • ■ 1 1 1 an- seen on the post-£ardinaI angle. 



Hamilton group. Canandaigua lake, X. Y. 

 Fig. 8. A large, broad right valve showing an unusually short hinge-area. 



Hamilton group. Bellona, Yates Co., N. Y. 



GOSSELETTIA TRIQUETKA. 



Page -2G5. 



See Plate 87. 



Fig. i*. A view of the U>l't valve of a young individual of this species. 



Fig. W. The right side of a very ventricose specimen preserving the natural form. Supposed to be the 



original specimen. 

 Figs. 11, 13, 14. The Left, cardinal ami posterior views of a specimen preserving the natural convexity 

 and showing the posterior teeth of the left valve. 

 Hamilton group. On mdaga '".. N. Y. 

 Fig. 1-. The anterior side "t a similar specimen showing the anterior muscular impressions. 

 Hamilton group. Onondaga ('".. X. Y. 



Fiir. 15. A partial east of a left valve. The beak ha- i a removed to show the strong anterior teeth and 



anterior muscular impre: 



Hamilton group. Fultoriham, Schoharie Co., X. Y. 

 Fig. 16. A large left \ all e presen ing the surface markings and the ligamental area. 



Hamilton group. Fultonham, • Co., N. Y. 



Fig. 17. A large right valve. 



Ham ison Co., JV. Y. 



