AMERICAN SPECIES OP VERTIGO. 75 



Specimens of all of the American species except V. arthuri 

 have been examined in the course of this work, including types, 

 paratypes or specimens from the describer of all except a few 

 of the older species. 



SPECIES OF BERMUDA. The species, while strongly differen- 

 tiated, are evidently related to forms of the eastern United 

 States. 



V. marki Gul., no. 18 (related to V. tridentata) . 



V. numellata Gul., no. 7 (remotely related to the ovata 

 group). 



V. bermudensis Pils., no. 33 (related to V. milium). 



SPECIES OF THE WEST INDIES. These tropical forms may 

 be presumed to be of northern origin, since all of them are 

 either identical with species of the United States or at least 

 not satisfactorily shown to be different. Possibly all may 

 be importations within the period of commerce ; I cannot other- 

 wise understand the absence of differentiation in those I have 

 been able to examine. The following have been recorded. 



V. ovata Say, no. 4. Cuba, Haiti, Porto Rico. 



V. neglect a Poey. Cuba ( ? = = ovata, no. 4) . 



V. hexodon C. B. Ad. Jamaica ( ? = ovata, no. 4) . 



V. gouldii Binn., no. 11. Jamaica, Cuba, St. Croix, Tortola. 



V. milmm Gld., no. 32. Jamaica. 



V. cubana Dall. "Cuba" (= Hawaiian Lyropupa). 



Key to American groups of Vertigo. 



a 1 . Columellar lamella crescentic, its inner end turning down- 

 ward; lower palatal fold entering to the dorsal side and 

 turning down at the end. Teeth all well developed. 



Subgenus ANGUSTULA, species nos. 32, 33. 

 a-. Columellar lamella subvertical ; lower palatal fold short, 

 a conspicuous external constriction over it (pi. 8, fig. 10) ; 

 3 or rarely 4 small teeth. Southern states. 



Subgenus VERTILLARIA, species no. 31. 



a 3 . Columellar lamella short, entering horizontally or ascend- 

 ing inwardly, or wanting. Subgenus Vertigo. 

 & 1 . Lower palatal fold entering to the dorsal side; 6 

 well developed teeth ; a very high crest. Bermuda. 

 Group of V. numellata, species no. 7. 



