Branson — The Fauna of the Residuary Aitburn Chert. 45 



HORMOTOMA LATIANGULARIS, 11. Sp. 



PL vii. f. 13. 



Shell very small, four millimeters high, three milli- 

 meters wide ; apical angle fifty-seven degrees. Volutions 

 five, increasing rapidly in size, lower volution forming 

 considerably more than half of the shell. Band compara- 

 tively broad, slightly convex, the convexity giving to the 

 upper volutions a subangular appearance. Notch shal- 

 low, slightly above the middle of the whorl. Lines of 

 growth curved slightly backward on the upper side of 

 the whorls. 



Ilormotoma latiangidaris can be readily distinguished 

 from all other species of Honnotoma by its wide apical 

 angle, low spire, and convex band. 



Species based on a single perfect specimen. Number 

 11552 of the invertebrate paleontological collection of 

 "Walker Museum. 



HORMOTOMA FASCIATA, U. Sp. 



PL vii. f. 16. 



Shell large, very loosely coiled, apical angle about six- 

 teen degrees. Band narrow, convex, considerably ele- 

 vated. Suture very deep, lines of growth coarse, bend- 

 ing strongly backward from the suture to the band. 

 Aperture slightly higher than wide. 



This species differs from H. gracilis in being more 

 loosely coiled, having a very considerably raised band, 

 the lines of growth bending backward more strongly, and 

 the notch being deeper. 



This species is based on two specimens. Numl)er 11509 

 of the invertebrate paleontological collection of Walker 

 Museum. 



PTEROTHECA EXPANSA. EmmOUS. 



PL vii. f. 14. 



Emmons, Natural History of New York, 4:397, 1842. 

 A single specimen which is referred with some doubt to 

 this species. It differs from the specimen figured by 



