Natural ffistorv Notes fro^ti North Carolina. 93 



as is life itself. Tliis subject may be discussed in detail liere- 

 after should the occasion demand. 



5. Mesodon thyroidcs, vSay. This species is rare here. The 

 specimens are in every way normal, so far as I have collected 

 them. 



6. Mesodon -a'/icaf/eyi, Bland. This rare shell has the same 

 distribution as number three. In the lower part of its range, 

 the shell is larger and heavier, but as we approach the summits 

 of the mountains it becomes thinner and lighter, as well as 

 smaller. It seems to prefer hiding away in crevices of the 

 rocks, and it is hard to find except during rainy weather. 



7. Mesodoji profundus, Say. This species occurs here in 

 fair numbers, presenting the same varieties that are familiar 

 to Cincinnati collectors, but of rather smaller size than the 

 Ohio and western shells. 



8. Mesodon diodonta. Say. This species occurs sparingly, 

 and seems to have its vertical limit with tliyroidcs and pro- 

 fundus, at about 4,500 feet. At least this is as high as we 



have collected it. The shells differ in no respect from other 

 Appalachian examples of the species from the north and east. 



9. Mesodon zvetherbyi, Bland. Shells, which have been 

 referred to this species, have been collected here by us, and 

 were taken by myself and students in 1881. In ray Notes on 

 American Land Shells, published in this Journal for that 

 year, I fully discussed the differences between this form and 

 the typical ivetherhyi, and suggested its relationship to 

 Triodopsis. 



Recently {The Nautilus^ May, 1893,), the eminent Con- 

 servator of Mollusca at the Philadelphia Academy of Sciences, 

 H. A. Pilsbry, has, after quoting in full any remarks above 

 referred to, described the present form as Triodopsis suhpalliata. 

 Upon a careful comparison, recently, with the types of 

 Mesodjio wetherbyi, I am inclined to believe that if we are to 

 make species of these connecting links, this is as distinct as 

 any of them, though in a series representing all the varieties 

 of dentifera, appressa, palliata and the present form, it might 

 be very difficult to say which are " species " and which are not. 



