Xii INTRODUCTION. 



Subfamily Vertigininae. 



Vertigininae Pilsbry, in part, vol. 25, p. 68. 



Vertigininae and Truncatellininae Steenberg, 1925, p. 201. 



Shell small or minute, usually brownish, compact, oval or 

 cylindric ; aperture with many teeth or none. 



Animal oviparous, usually without tentacles. Penis simple, 

 without appendages, the retractor muscle simple, attached to 

 epiphallus. Hermaphrodite gland divided into two groups of 

 short, wide acini. Male organs are frequently absent. Jaw 

 formed by the concrescence of relatively few, wide plates 

 separated by grooves. Central tooth tricuspid, laterals bi- or 

 tricuspid with interstitial cusplets, the ectocone often about 

 as long as the mesocone. Marginals usually tricuspid with 

 numerous interstitial cusplets. The genera fall into two series. 

 Genera starred have been dissected. 



1. *Vertigo, 25:68. 



2. •Truncatellina, 26:59. *Columella, 27:232. 



