24 Bulletin 22 24 



plate v 



Page 



Fig. 1. Segaretus (Sigaticus) clarkensis Aid 12 



2, 3. Discohelix texana Aid 12 



4-6. Chlorostoma nautiloides Aid 12 



7, 8. Neritina unidenta Aid 13 



9, 10. Argyrotheca dalli Aid 13 



