PLATE XLIL Continued. 



PAOE. 

 Figs. 56 and 80. CTENODONTA SOCIAI.IS, n. sp 504 



60. Outline views of three specimens of different sizes and showing slight variations in form. 

 CO. Hinge of two right valves, X 8. showing slight differences In the anterior parts. 



Figs. 81 to 64. CTENODONTA CALVINI, n. sp 596 



61. An excellent cast of the Interior of a left valve, showing muscular scars and rays more plainly than 



usual. In this specimen the length also Is a little greater than in the others. 



62. Another cast of a left valve. Minn. Oeol. Sur. Mus. Reg. No. 8028. 



63 and 64. Lateral and cardinal views of a cast of a right valve, representing the usual characters of the species. 



Figs. 65 and 66. CTENODONTA MADIBONENSIS, n. sp 597 



The left side and an anterior view of a testlferous example of this species. 



Pigs. 67 to 73. CTENODONTA FECUNDA Hall r>95 



67 and 68. The right side and an anterior view of a cast of the Interior. In many specimens the posterior 



margin Is more rounded 



60. A small part of the external surface magnified to snow the fine concentric and radiating lines. 

 70 to 72. Cardinal and anterior views and the right side of a specimen preserving the shell. 



73. The wavy hinge line as shown on a cast of the interior, X 5. 



Figs. 74 and 75. CTENODONTA RIMTLATKIX. n. sp 600 



74. A cast of the Interior of a right valve, showing the muscular scars and retaining a little of the shell 



about the beak. 



75. As much of the hinge as can be made out from the preceding specimen. 



Figs. 76 to 82. CTENODONTA AI.BEKTINA, n. sp 596 



76 to 78. Three views of a large specimen having the posterior end a little narrower than usual. 



79. A smaller specimen of the usual form. 



80. Hinge of a large and smaller right valve, showing the subrostral pit and the genlculated teeth. 

 81 and 82. Cardinal and lateral views of a cast of the Interior which retains a part of the hinge. 



Figs. 83 to 87. CTENODONTA OBUQUA Hall 604 



83 and 84. Lateral and cardinal views of a small specimen of the large northwestern variety of this species, X 5. 



As usual, the specimen Is a cast of the Interior and shows the muscular scars and impresslonsof the 



hinge denticles very clearly. ' 

 86 to 87. Three Internal oasts of a small form of the species from the Cincinnati group of Ohio, X 5. 



FIgs.88 to 90. CTENODONTA COM PRESS A Ulrlch 



(See also plate xxxvn, fig. 29.) 

 88 and 80. Posterior and lateral views of a left valve. 



GOO 



00. 



The greater part of the hinge of another left valve, X 5, showing the various parts In a beautiful 

 state of preservation. 



005 



602 



Figs 91 and 92. CTENODONTA HAMBURQENSIB Walcott 



A rlL'ht (?) valve of the natural size and X 5. 



Figs. 03 and 94. CTENODONTA AI.TA ITall 



Lateral and posterior views of a cast of the Interior. 



Figs. 95 to 07. CTENODONTA INTERMEDIA Ulrlch 601 



95 and 06. Lateral and posterior views of a right valve preserving much of the shell. The opposite valve Is 



restored In the profile view. 



97. A sharply marked cast of the Interior of a left valve. In this specimen the posterior extremity Is 

 unusually produced. 



Figs. 88 to 101. OTENODONTA RECUHVA Ulrlch 602 



98 to 100. Posterior, lateral and cardinal views of a perfect specimen of this species, showing the usual form, 

 the anterior sulcus and the sharply defined anterior and posterior lunettes. 



101. The greater nart of a hinge of a left valve, X 2, showing the arrangement of tin' clrntlrlrs, tin- 



sharply elevated outer margin and the llgamental area on the right side of the beak. 



Figs. 102 to 106. OTENODONTA BIMIUB Ulrlch 604 



102. Hinge of a left valve of this species, X 2, showing the principal features upon which this species Is 



separated from ('. reeurva. (See fig. 101.) 



103. The left side of a specimen, showing the usual form of the species. Minn. Oeol. Sur. Mus. Reg. 



No. 8368. 



104 to 106. Lateral, cardinal and posterior views of a specimen having an outline very similar to that of 

 C. reeurva. But the absence of the anterior siilcus, the greater convexity of Its valves and the 

 less sharply denned lunettes are all characteristic of C. fimilin and prove its distinctness from 

 C. ncvrva. 



