1906.] NATURAL SCIENCES OF PHILADELPHIA. 567 



17. Sampson, F. A. Notes on the Distribution of Shells. Kansas City Review 



of Science and Industry. 



I. SheUs of Eureka Springs, Ark. Vol. V, p. 526, 1881. 

 II. Shells of Fort Worth, Tex. Vol. V, p. 681, 1882. 

 III. Shells of Sedaha, Mo. Vol. VI, February, 1883, p. 551. 

 IV. Lamar, Barton Co., Mo.; Springfield, Mo.; Eureka Springs, Ark. Vol. 



VI, pp. 22-25. 



18. . Shells of Pettis Co., Mo. Bulletin Sedalia Natural History Society, 



August, 1885, pp. 16-28. 



19. . Notes on the Distribution of Shells. American Naturalist, 1887, pp. 



83-86 (On Gastropods collected in Northwestern Arkansas in March, 1886) . 



20. . A Preliminary List of the MoUusca of Arkansas (exclusive of the 



Unionidse). Ann. Rep. Geol. Survey of Arkansas for 1891, II, pp. 179-199, 

 1893. 



21. . Mesodon andrewsi in Missouri. Nautilus, VI, p. 90. 



22. . Southern Shells in Missouri. Nautilus, VIII, p. 18. 



23. . MoUusca of Arkansas. Nautilus, VII, pp. 33-35. 



24. . Some Arkansas Snails. Nautilus, VIlI, p. 36. 



25. Simpson, Charles T. Notes on Some Indian Territorv Land and Fresh- 



water Shells. Proc. U. S. Nat. Mus., 1888, pp. 449-454. 



Explanation of Plates XX, XXI, XXII. 



Plate XX. — Figs. 1-5. — Pohjgyra jacksoni, Petit Jean Mountains, Ark. 

 Figs. 6, 7. — Polygyra jacksoni deltoidea, Fort Gibson, I. T. Cotypes. 

 Figs. 8, 9, 10, 11. — Polygyra jacksoni simpsoni, Wyandotte, I. T. Cotj^pes. 

 Figs. 12. — Polygyra dorfeuilliana, Mammoth Spring, Mo. 

 Figs. 13-16. — Polygyra dorjeuilliana, Hardy, Ark. 

 Figs. 17-19. — Polygyra dorfeuilliana sampsoni, Wyandotte, I. T. 

 Figs. 20, 21, 22. — Polygyra dorfeuilliana perstriata, Mena, Ark. 

 Fig. 23. — Polygyra dorfeuilliana percostata, Red River, Ark. Cotype. 

 Fig. 24. — Pohjgyra dorfeuilliana perstriata, Tushkahoma, I. T. Cotype. 



Plate XXI. — Figs. 1, 2. — Polygijra indianorum, Tushkahoma, I. T. 

 Figs. 3-8. — Polygyra indianorum, Limestone Gap, I. T. 

 Figs. 9-11. — Polygyra binneyana, Petit Jean Mountains, Ark. 

 Fig. 12. — Polygyra binneyana, Sugar-loaf Mountain, I. T. 

 Fig. 13. — Polygyra kiowaensis. Magazine Mountain, Ark. 

 Figs. 14, 15. — Polygyra indianorum lioderma, Red Fork, I. T. Cotypes. 

 Fig. 16. — Polygyra binneyana chastatensis, Chastat Mountains, Ark. Co- 



tjTJe. 

 Figs. 17, 18. — Polygyra kiowaensis (types oi war. arkansaensis), Hot Springs, 



Ark. 

 Fig. 19. — Polygyra kiowaensis, Limestone Gap, I. T. 

 Fig. 20. — Polygyra kiowaensis, Kiowa, I. T. Cotype. 



Plate XXII. — Fig. 1. — Polygyra inflecta Say. Type. 



Figs. 2, 3. — Pohjgyra inflecta, Chadwick, Mo., form No. 1. 



Figs. 4-6. — Polygyra inflecta, Chadwick, Mo., form No. 2. 



Figs. 7-9. — Polygyra inflecta, Wyandotte, I. T. 



Fig. 10. — Polygyra inflecta media, Seligman, Mo. Type. 



Fig. 11. — Polygyra edentata, Chester, Ark. 



Figs. 12-14, 17, IS. — Polygyra edentata magazinensis. Magazine Mountain, 



,\rk. Cotypes. 

 Figs. 15, 16. — Pohjgyra edentata Porter, Ark. 

 Figs. 19, 20, 21. — Polygyra neglecta, Chadwick, Mo. 

 Figs. 22-25. — Polygyra elevata. Hardy, Ark. 



Figs. 26-29. — Polygyra zaleta ozarkensis, Sugar-loaf Mt. Cotji^es. 

 Figs. 30-32. — Polygyra obstricta occidentalis, Northern Ark. Cotj-pes. 



