INTRODUCTION 



KEY TO THE GENERA OP TORNATELLINID^E. 



a. Shell imperforate, the columellar axis solid throughout. 

 6. Shell globose or broadly ovate ; columella conspic- 

 uously calloused. 



c. Whorls few, 3 to 4% ; apex large ; columellar 

 callous bilobed; aperture and throat ample 

 (pi. 28, fig. 6). ELASMIAS, p. 113. 



c 1 . Whorls about 6 or 7 ; apex small; columella 

 having numerous, deeply entering lamellae, ob- 

 structing the throat (pi. 28, figs. 10-12). 



LAMELLOVUM, p. 131. 



ft 1 . Shell ovate, ovate-conic, oblong or turrited-conic ; 

 columella often lamellate but not heavily calloused 

 within. 



c. Lip thin, sharp and unexpanded; shell thin 



or fragile, uniform brown or corneous, dex- 



tral. TORNATELLINA, p. 132. 



c 1 . Lip more or less expanded, not sharp; shell 



moderately strong or solid, often dark or 



bright colored or banded. AURICULELLA, p. 71. 



a 1 . Shell perforate or umbilicate in the last whorl, above 



which the axis is solid. 



b. Lip expanding, thickened within or blunt-edged ; 

 shell often strongly colored or banded. 



AURICULELLA, p. 71. 



fr 1 . Lip not expanding, thin and sharp-edged; shell 

 small (3% mm.). GULICKIA, p. 112. 



a 2 . Shell perforate or umbilicate, the axis perforate through- 

 out; thin or fragile, less than 6 mm. long. 



(vii) 



