28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



thicker, convexly curved mesopore diaphragms forming a cystose 



pattern. 

 Fig. 3b. Longitudinal view of lectotype, X 100, showing notched acanthopore, 



typical of those found in most species of Batostoma. 

 Fig. 3c. Tangential section of lectotype, X 50, showing polygonal mesopores, 



oval, thin-walled zooecia, and acanthopores with structureless cores. 

 Fig. 4. One of two original longitudinal sections of paratype, X 50, showing 



convexity of diaphragms in mesopores. U.S.N.M. 43614. 



