PLATE LXXXVI. 



Glyptodesma erectum. 



, Page 153. 

 See Plates 11, 12. 13, 25 and 87. 



Fig-. 1. A left \alve of a small individual. 



Hamilton group. FahinJ!, Onondaga Co., N. Y. 

 V\g. 2. The light valve, as seen lying- within the left, showing its form and comparative size. 



Hamilton group. Cayuga lake, N. Y. 

 Fig. 3. The hinge of a specimen, showing the striated ligamental area and strong cardinal folds.  



Hamilton group. Delphi, Onondaga Co., N. Y. 

 Fig. 4. A small left valve with small anterior wing and very large posterior wing, also showing one of the 

 olilique lateral teeth. 



Hamilton group. Cayuga lake, N. Y. 

 Fig. 5. The anterior profile view of a very perfect specimen retaining the test, showing the comparative 

 convexity of the valves. 



Hamilton group. Pratt's falln, Onondaga Co., N. Y. 

 Fig. 6. The left valve tig. 8, phitt; 11, redrawn to show the ligamental area, lateral teeth and muscular 

 impression. The tubular markings around the mai-gin are the remains of the excavations 

 made by boi-ing sponges. 



Hamilton group. Cazeiurvia, N. Y. 

 Fig. 7. A large right valve, showing the ligamental area, pallial line, muscular impression and umbonal pits. 



Hamilton group. Gilberts-inlle, Otsego Co., N. Y. 

 Fig. 8. A left valve presenting the same internal charactei-s as the precetling, together with two strong 

 lateral teeth. 



Hamilton group. Albany Co., iV. Y. 



Gl.VrTODESMA OCCIDENTALE. 



Page 157. 

 See Plate 15. 

 Fig. 9. The Mi)ecimen of iig. 12, plate 15, redrawn to show the erect form of the body and extent of the 

 posterior cardinal expansion. 



Upper Helderberg gi-oup. Falls of the Ohio. 



