Plate 14. 



Pig. 1. Lituola mexicana. X 40. End view. 



2. Lituola mexicana. X 30. Last chambers in section. 



3. Lituola mexicana. X 30. Pores of the interior wall of one of the earliei 



chambers. 



4. Lituola mexicana. X 15. D2399, U.S.N.M. No. 10698a. 



5. Placopsilina cenomana. X 20. D2371, U.S.N.M. No. 10551. 



6. Placopsilina con/usa. X 20. D2115, U.S.N.M. No. 10549. 



103 



