1888.] NATURAL SCIENCES OF PHILADELPHIA, 137 



Fig. 5. Orthis acutiloba, n. sp. 



a. Ventral view enlarged three diameters. 



c. Dorsal view enlarged three diameters. 



d. Profile view enlarged three diameters. 



Fig. 6. Orthis hiloba Lin. Outline of a species from Walcott, 

 N. Y. in my collection to show the difference in contour from 

 0. acutiloba. 



Fig. 7. HyolithU subimbrimtus, n. sp. 



Fig. 8. Plumulites gracilissimus, n. sp. 



a. Same enlarged three diameters. 



^* 



10 



