332 AMERICAN JOURNAL 



MESESCHIZA, Lea. 



1. M. Grosvenorii, Lea. Fig. 1. Smooth, fusiform, thin, 

 obtusely conical ; suture slightly impressed; whorls 7, slightly 

 convex, the last large ; aperture large, rhomboidal ; lip acute, 

 in the middle slightly cut. Greenish-purplish within and 

 without, sometimes banded. Wahash River, Ind. 



Fig. 1 is from the type. 



SCHIZOSTOMA, Lea. 



Synoptical Table of Species.* 



Fissure direct, narrow, and deep. Fissure oblique, short, and loide. 



1. Shell striate or ridged. 



a. Shell conical; spire lengthened, sharply carinate. 



1. S, CAEINIFEEUM, Anth. 15. S. PAGODUM, Lea. 



S. SliowaJterii, Lea. 16. S. pyramidatum, Shutt. 



2. S, CASTANEUM, Lea. 17. S. Wetumpkaense, Lea. 



S. ornata, Anth. 

 S. pagoda, Lea, of Reeve, 

 b. Shell conic-cylindrical; spire obtuse, not carinate. 



3. S. ovoideum, Shutt. 18. S. Alabamense, Lea. 



19. S. Anthonyi, Lea. 



4. S. EXCisuM, Lea. 20. S. babylonicum, Lea. 



S. Spilmanii, Lea. 

 c. Shell globosely-ovate ; spire moderate. 



5. S. PUMILUM, Lea. 21. S. Buddii, Lea. 



S. globosum, Lea. S. funiculatum. Lea. 



^S'. Alabamense, Lea. S.pagodum, Lea, of Reeve. 



S. Showalterii, Lea, of Reeve. 



2. Shell smooth. 

 d. Shell elliptic. 



6. S. ELLIPTICUM, Anth. 



7. S. LACINIATUM, Lea. 



e. Shell quadrately cylindrical. 



8. S. AMPLUM, Anth. 22. S. demissum, Anth. 



9. S. NUCULUM, Anth. S. Rartmanii, Lea. 



23. S. CONSTRICTUM, Lea. 

 S. rectum, Anth. 



* The ScMmostomm contain two nearly equal groups, characterized re- 

 spectively by a narrow, direct, and an oblique, short, wide slit. 



In the above table the opposite species in the two groups are generally 

 exactly similar, except in the character of the sht ! 



