28 



— n\ore or less ovate, or ovate conic, parietal lam. of 



moderate size; .ipparently simple [as a rule.] 6 



6 last whorl not r::uch higher than preceding, usually 

 with a distinct crest on the palatal wall, behind the 

 aperture; lam. and folds usually 5, but up to 8 or 9: 

 parietal, columellar, basal and 2 palatals of which 

 the inferior is the longest; sometimes a nodule be- 

 tween the parietal and the columella, and 2 to 3 ad- 

 ditional in the palate; alt. 2, diam. i mill. 



curvidens, Gld, 



A^ote. — Var. gracilis: cylindrical, always with 5 lam. and folds. 



— last whorl somewhat predominating, without a crest 



on the palatal wall; aperture comparativ-ely larger 

 and more rounded; lam. and folds: parietal, colu- 

 mellar, basal, 2 palatals, the inferior scarcely longer; 

 almost ahva3s there are 3 to 4 additional folds in 

 the palate; alt. 2.5, diam, 1.2 mill. pentodon, Say 



19. Vertigo, Mull. 



1 Inferior palatal fold vtry long, its inner part high, 



thin, curved downward, superior as usual, with 

 each of them a corresponding depression on the 

 outside; 2 lam. on the parietal wall: the angular 

 and the parietal; columellar, i basal; sh. very 

 small, ovoid, deep hoin to chestnut colored; peri- 

 stome everted, on the right side with an indenta- 

 tion; alt. 1.3, diam o.S mill. 

 [Subg. Angustula.] milium, Gld. 



— palatal folds as usual; parietal lam. i, or, if more, 



sh. larger. 2 



2 surface of the middle whorls vvitli regular, fine stria?, 



no, or a thin callus in the palatal wall; lam. and 

 folds 5 [4] : I parietal, i columellar, 2 palatals, ra- 

 ther small, one basal [often wanting]; sh. cylin- 

 drical-ovate, with the apex rather obtuse: alt. 1.8, 

 diam. i mill. gouldii, Binn. 



