PLATE XXIII. 



Leptodesma jjav ifokme. 



Page 200. 

 : I : See Plate 22. 

 Fig-. 1. A right valve showing- the characters of the shell. 

 Chemung g-roup. Near Ithaca, N. Y. 



ACTIXOPTERIA PEKSTRIALIS. 



Page lis. 



See Plate 84. 

 Fig-. 2. A loft valve. 

 Fig-. 7. A rig-ht \ al\"e of a l:irg-cr example. 



Chemung- gfoup. Ithaca, N- i'. 



ACTINOPTEKIA DELTA. 



Page l-'l. 

 Fig-. ?: The left v.-ilv(! described. 



(^houiuiig- gronp. Ithaca, JV. Y. 



ACTtXOPTEUIA EPSILOX. 

 Page 12-2. 



Fig. 4. A small left valvft.  : . _ ., 



Figs. .^, 6. Two left valves refei-i-ed to this species with some dmibt on .nccoaiit of theii- liner surface radii. 

 Fig-. 8. An imj^ressiou of a left valve, retaining that of the rig-ht vah-e beueatli it in the centre, thus show- 

 ing partly the features of both. 



(Chemung g-roup. Ithaca, JY. Y. 



xVCTINOPTERIA ZETA. 

 Page Hi. 

 See Plate 84. 

 Fig. 51. A i-ig-ht \-alve showing the form and surface ornamentation, with two oblique lateral teeth. 

 Chemnng gronp. Ithaca, iV. Y. 



Ptychoiteeia expansa. 



Page 1.5-2. 

 Fig. 10. The left \-alve describe<l showing the form and surface .OTOamentation. The body is represented 



as too narrow and there shoXUd be a slight fm-row limiting- the wing. 

 Fig. 11. An enlargement of the snrface from the anterior nmbonal slope, showing the direction of the radii. 

 Chemung grcuvp.; Slmethport, Pn. 



PxYCIiOPXEKIA PeOTO. 



Page 129. 

 Figs. 12, 14. Two left valves. The wings in each one .shonld be limited liy a slight fnrruw. 

 Chemung g-rouij. Near Smethport, Pa. 



