1902.] NATURAL SCIENCES OF rHILADELPHIA. 435 



The sjiecimens now l)ruught to light demonstrate the necessity of 

 recognizing the race. It differs from G. g. Icnvce ( W. G. B. ) in 

 the much narrower umbilicus ; from G. gularis of the Great Smoky 

 mountains in being tootliless in the adult stage, and with a more 

 excavated base and straighter basal lip. Xo adult .shell, in a large 

 number examined, possessed internal laminre. 

 Gastrodonta gularis lawae (W. G. B.). PI. XXV, figs. 10, 11, 12. 



Zonites placentuhis (ShuttL), W. G. Biuney, Terr. Moll. U. S , V., p. 

 124, fig. 44, PI. Ill, f. L, (dentition) and remarks, but not the 

 description (1878). 

 Zonites hismodon var.? W. G. Biuuev, Auu. X. Y. Acad. Sci., I, 



pp. 3i8-362, PI. 15, f. e. (1879). 

 Zonites lawi \\. G. Binuey, 1st Supplement to Terr. Moll., Y, p. 

 142, PI. 2 (reprint of PI. 15, Auu. X. Y. Acad. Sci., I), fig. e 

 (1883). Manual of Amer. Land Shells, p. 221, fig. 235. 



The shell is yellow, glossy, with moderately elevated, dome-like 

 spire, composed of 8 closely coiled whorls; surface rather chjsely 

 wrinkle-striate, the strise strongest near the suture, weaker below, 

 where a few faint spiral strise may be traced. Last whorl rounded, 

 hardly angular, even in front. Umbilicus wide, open, deep and 

 well-like, the bases of the first whorls visible in its depth. Aper- 

 ture small, irregularly lunate ; peristome acute, strengthened « ithin 

 by a rather thin, diffused white callus, which becomes heavier 

 within the columellar margin, making a slight convexity or low 

 boss near the axis. Columellar margin somewhat straightened. 

 Alt. 4.7, diam. 7.8 mm., width of umbilicus 1.3 mm. 



The above description and figures 10-12 represent the type shell, 

 Avhich differs from most other specimens in being without internal 

 lamellcTe. Binney (^Supplement, p. 143) mentions that "there is a 

 variety in which is a heavy internal callous or plate-like teeth within 

 the aperture, " and this (PI. XXV, figs. 14, 15, 16, 17) is certainly 

 the prevalent form in the localities collected at in 1901. These den- 

 tate specimens have the long, strong, arching basal lamella of G. 

 gularis cuspidata. AVhether the lamina-bearing form will eventu- 

 ally be separated from the toothless typical form remains for future 

 investigation, the material now available being insufhcicnt for a 

 decision. 



This race has not hitherto been defined, although Binney has 

 figured it in three publications. The figures, however, were not 

 good, and on account of its a.ssociation with the very different 

 G. placentnla (Shuttl.), it has not been generally recognized by 



