210 PROCEEDINGS OF THE ACADEMY OF [Feb., 



Shell similar to V. placentula m general form and size, but the 

 whorls increase more slowly, the last being narrower ; thin and fragile, 

 often sprinkled with buff dots. Teeth generally present, 3 to 5 being 

 arranged in a radial row, or with several such rows within the basal 

 wall, though the number of teeth may vary down to in the adult 

 stage, or less frequently at any stage of growth. Whorls S to Sh in 

 adults, which measure 7 to 8 mm. diam. 



In some localities, as around Roan Mountain, teeth are almost invari- 

 ably developed. In some other localities they are rare in adult shells, 

 and developed in the yomig ones only. Such toothless individuals 

 are separable from V. placentula by their slightly more fragile structure 

 and greater number of narrower whorls. 



In a multitude of shells examined from over a dozen localities, I 

 found one young specimen with a diameter of 4 mm. in which there 

 was a single radial barrier, such as occurs in T'. hnnellidens Pils." The 

 figures are from topotypes. 



Vitrea placentula (Shuttle worth). PI. XI, Pgs. i, la, 16. 



Zon. placentuhis Shuttl., Sterki, Nautilus, VII, p. 17 (1S93). 

 Vitrea capsella 'placentula Shuttl., Pils.. Proc. Acad. Nat. Sci. Phila., 1900, 

 p. 140. 



This species, if such it be, differs from V . capsella merel}' in the larger 

 size, and in having an additional whorl. Adult shells measure 7 mm. 

 diam. , and have 7 or 7^ whorls. I have never seen a specimen with teeth, 

 although a good many shells, adult and young, from the Great Smoky 

 Mountains and elsewhere have passed under my lens; but when very 

 young individuals of placentula are found, I think they will prove to 

 have pairs of teeth, at least in rare eases, as in capsella. It is a trifle 

 more solid than V. anclrewsw (W. G. B.), and in specimens of the same 

 size the latter has a whorl more. The range of V. placentula lies to 

 the southwest of that of V. andrewsa. It was not taken by Ferriss 

 and Walker in the valley of the French Broad river, nor in the Black 

 mountains. Sterki's suggestion that andrewsai is the young of placen- 

 tulus is not borne out by the facts now known. Over a large part of 

 the range of placentula, V. andmvsce does not occur. 



The figured specimen is from Philadelphia, Toudon county, Tenn. 

 Vitrea capsella (Old.). PI. XI. figs. 2, 3, 4, 4a, ib. 



Zonites capsella Gld., W. G. Binney, Man. Amer. Land Shells, p. 221. 



The type locality of this species is ''Tennessee." Two specimens 



"^ This specimen is No. 1G,963 of Mr. Bryant Walker's collection, taken by him 

 at Paint Rock, N. C, on the soutli side of the French Broad river, near tlie Ten- 

 nessee boundary. 



