184 University Geological Survey of Ka7isas. 



PLATE XVI. 



Myalina amp? a, (p. 139.) 



1. External view of shell. (After Meek.) 



16. Interior of same. Both reduced one-half. 

 Myalina congener is, (p. 142.) 



2. Exterior of specimen. (After Walcott.) 

 26. Another specimen. (After Walcott.) 



Pteria sulcata, (p. 126.) 



3. Left valve enlarged. (After Meek.) 

 Pteria longa, (p. 125.) 



4. Left valve of specimen. Natural size. 

 Limopteria marian, (p. 128.) 



5. Right valve. Natural size. (After White.) 

 56. End view of specimen. (After White.) 

 5c. Surface markings enlarged. 



Limopteria longispina, (p. 127.) 



6. (After Keyes.) 

 Myalina sivallovi, (p. 137.) 



7. Left valve. Natural size. 

 Myalina perattenuata, (p. 141.) 



8. Right valve of specimen. Natural size. 

 Limopteria gibbosa, (p. 129.) 



9. Right valve. (After White.) 

 Myalina subquadrata, (p. 138.) 



10. Impression of left valve. (After Meek.) 



106. Part of left valve broken away, showing the interior of the right valve 

 and outline of the specimen. (After Meek.) 

 Myalina kansasensis, (p. 140.) 



11. Specimen showing left valve. (After Keyes.) 



PLATE XVII. 



Aviculopinna illinoiensis, (p. 143.) 



1. Outline of cross-section. 

 16. Specimen. Natural size. 



lc. Surface markings. Enlarged. 

 Pinna subspatulata, (p. 145.) 



2. Drawing of cast. Reduced one-half. 

 Pinna peracuta, (p. 144.) 



3 and 36. Lateral and dorsal views. (After Keyes.) 



