218 PLANORBIS. 



10, 11, 12. Pl, Oregonensis, Tryon. Am. 

 Jour. Conch, i, 231, t. 22, f. 17, 

 1865. No. 15. 



15, 14, 15. Pl. fragilis, Dunker. Kiister's 



Chemnitz, 46, t. 10, f. 41—43. 

 Binney, 1. c. 122. 

 — Pl. trivolvis. Say. Hald. Monog. 13, t. 

 2, f. 4—7. 



16. Pl. macrostomus, Whiteaves. Canad. 



Naturalist, viii, 113, 1863. No. 16. 



17 — 19. Pl. truncatus, Miles. Winchers 

 Geol. Michigan, 238, 1861. No. 18. 



(«5) 



