THE NAUTILUS. 



Lake, Medina Co., 0., and then looked for others in vain, for 

 over a dozen years. It is evidently none of the described spe- 

 cies ; the jaw and radula are different from those of both caro- 

 linensis and dorsalis, but the jaw is more like that of the former, 

 without strong ribs. The other parts of the anatomy have not 

 been examined, and so it remained unpublished. The body,, 

 when extended, is about 28 mm. long, slender ; the dorsum is 

 tan-colored, without any markings. 



33. Ph. dorsalis Binney, not scarce. 



34. Strobilops labyrinthiciis Say, rare. 



35.* Vallonia pulchella Miiller, not in the woods, common 

 around a barn near by. 



36.* F. excentrica Sterki, with the preceding. 



37. Bifidaria contracta Say, common. 



38. B. pentodon Say, common; variable with respect to the 

 apertural lamella and folds. 



39. B. minuta Sterki; for description see page 105. 



40. B. corticaria Say, scarce. 



41. Vertigo goiddii Binney, not rare. 



42. V. ovata Say, scarce. 



43. V. elatior Sterkii, scarce. Appears to be distinct from 

 rentricosa, to judge by material from a number of States. 



44. V. tridentata Wolf, rare. 



45. V. milium Gould, rather scarce. 



46. Cionella lubrica Miiller, rather scarce. 



47. Succinea ovalis Say, common. 



48. S. retusa Lea, scarce. 



49. S. avara Say, scarce. 



50. Carychium exiguum Say, scarce. 



51. C. exile H. C. Lea, common. 



52. Lymmea parva Lea, scarce. 



a. * L. parva sterkii F. C. Baker (probably, according to F. 

 C. Baker) ; ditch, outside. 



53. L. ? (small, slender, probably immature), two speci- 

 mens in siftings, with land snails. 



54. Planorbis trivolvis Say, in a permanent pool, or small 

 pond. 



55. P. exacutus Say, pools (with 61), not rare. 



