North American Helicidce. 297 



former figure in his Synonymy of H. Dysoni. Reeve, in ex- 

 planation of his figure, says, — " the specimen here figured has 

 no teeth on the inner wall of the aperture, it being as com- 

 monly absent as present." I have examined many specimens 

 of Lea's shell, and have seen none without the parietal tooth. 



Pfeiffer also refers, but with doubt, to the figure in Fer. 

 Hist. t. 69 D. fig. 3, which is, as I have shown, II. fatigiata 

 Say, and in Mon. III. p. 264, he increases the confusion by 

 adding II. finitima Desh. {plicata Say) to the Synonymy of 

 Dorfeuilliana Lea. 



It may be noticed that Honduras, and the habitats in the 

 United States of Lea's species, are in distinct zoological pro- 

 vinces, — I do not know any species of Helix common to 

 both. 



H. Dorfeuilliana Lea differs materially in its characters 

 from the three preceding species ; the striae on the upper sur- 

 face are not so well defined as in Troostiana, but more so than 

 in Hazardi, while the base is more smooth than in either of 

 them, having only very delicate striae, with microscopic im- 

 pressed spiral lines. 



The parietal tooth is quadrate, — the two teeth on the right 

 lip are more nearly of the same size and form than in fatigiata 

 and Troostiana. In this species the inferior tooth is transverse, 

 and in some specimens broader than the superior one, but has 

 a somewhat pointed apex, — both are very nearly equally 

 deeply seated, but so far apart as to allow a view between 

 them into the aperture, leaving, as Mr. Lea expresses it, " to 

 appearance three nearly square apertures." Say would have 

 described the two teeth as " separated by a remarkable sinus." 

 The peristome of this is more thickened and less reflected than 

 in the other species, — behind it is deeply constricted, without 

 any appearance of pits showing the position of the teeth 

 within. 



H. Dorfeuilliana Lea varies in size, — the following are the 

 measurements of my largest and smallest specimens : — 



