NATURAL SCIENCES OP PHILADELPHIA. 237 



Fig. 7. Hemphillia glandulosa, Bl. and Binn. 



a. Central and first lateral teeth. 



b. Transition from lateral to marginal teeth. 



c. Marginal teeth near the edge of the membrane. 



d. Extreme marginal tooth. 



Plate VI. 



Fig. A. Tebennophorus Caroliniensis, Bosc. 



a. The central tooth. 



b. The first lateral. 



c. The last laterals. 



d. Marginal teeth. 



e. Extreme marginals. 

 Fig. B. Pallifera Wetherbyi. 



a. Central and lateral tooth. 

 6. Extreme marginals. 

 Fig. C. Pallifera dorsalis, Binn. 



a. Central and two lateral teeth. 



b. Marginal tooth. 



c. Extreme marginal. 



Fig. D. Orthalicus undatus, Brng. The central and first, second, 



fifteenth, fort^-eighth, and fiftieth marginals. 

 Fig. E. Liguus fasciatus, Mull. 



a. A group of central and marginal teeth. 



b. Marginal far removed. 



c. An extreme marginal. 



d. A marginal in profile. 



Plate VII. 



Fig. 1. Patula strigosa, Gld. 



a. Central and lateral teeth. 



b. Marginal teeth. 



c. Outer marginal tooth. 



d. An outer lateral on a different scale of enlargement. 



e. A central tooth from an embiyonic specimen. 

 Fig. 2. Patula Cooperi, W. G. B. 



a. Central and lateral. 



b. Outer marginals. 

 Fig. 3. Patula perspectiva, Say. 

 Fig. 4. Patula Idahoensis, Newc. 



