PLATE IX. 



Crenipecten Winchelli. 



Page 89. 

 Figs. 1, 2, 4. Small rig-ht valves showing the form of this valve and the obsolescent surface markings. 

 Figs. 25, 26, 27. Three left valves. Fig. 25 incorrectly represents the specimen as having the form of a 

 light valve. The beak should turn slightly toward the left and the posterior margin 

 should be more extended. 

 Fig. 28. The upper portion of a left valve, enlarged to two dianieter.s, showing the form and surface 



characters of the ears, and the tran.sverse ligamental grooves or cartilage pits. 

 Fig. 29. An enlargement of the surface as obtained from au impression taken in the natural mould of the 



exteiior. 

 Fig. 30. An enlargement as shown in an impression of the exterior left in the matrix. 

 Waverly sandstoiie. Ntnoark. Ohio. 



AVICULOPECTEN (CliENIPECTEN ?) INCULTUS. 



Page oO. 

 Fig. 3. An impression of the interior of a right valve. 

 Chemung group. Glean, N. Y. 



AviCULOPECTEN CaROLI. 

 Page 29. 

 Fig. 5. A partially exfoliated left valve. 



Waverly sandstone. NewarTt, Ohio. 



Crenipecten crenulatds. 



V3.ee S'2. 

 Figs. 6-8. Three left valves varying somewhat in form and obUquity. i 

 Chemung group. Rockville, Alleghany Co., iV. Y. 

 Fig. m. A right \-alve showing the form of this N.ilve and the row of minute cartilage-pits along the hinge. 

 The posterior ear is not sufficiently extended in the figure. 

 Chemung group. Philipshii,rg, Alleghany Co., N. Y. 

 Fig. 16. A light valve. The posterior ear in the specimen is somewhat larger than represented. 

 Pig. 17. An enlargement, to two diameters, sho^ving the row of cartilage-pits along the hinge. 

 Chemung grouj:). Rockville, N. Y. 



