North American Terrestrial MoUusls. 169 



narrow, uniform teeth, bearing a broad, expanded, recurved, 

 gouge-shaped cusp. 



Genus SxENOGYiiA (p. 228). — Central teeth of the lingual 

 membrane very small, tricuspid ; laterals large, subquadrate, 

 tricuspid, middle cusp very large; marginals subquadrate, 

 obtusely denticulated. 



Subfamily Succinin.e (p. 255). — To our description of 

 the lingual teeth must i)e added, " marginal teeth quadrate, 

 crowded, dent;ite or serrate." 



JVote on Helix inversicolor Fer. and other species from 

 Mauritius. 



While the foregoing paper was being printed, we had, 

 through the kindness of Mr. J. G. AnJiony, of the Museum 

 of Comparative Zoology, Cambridge, and of Mr. J. H. 

 Thomson, the opportunity of examining the animals of Helix 

 inversicolor Fer., H. leucostyla Pfr., //. rufozonata H. Ad. and 

 H. militaris Pfr., received from Mr. Pike, the United States 

 Consul at Mauritius. The results of such examination are 

 so interesting that we now publish them, 



H. inversicolor and H. militaris are placed by v. Martens 

 in Helicacea, genus Helix, the former in the section Caraco- 

 lus, and the latter in Stylodon, but both, as well as H. 

 rufozonata and leucostyla, rather belong to Vitriiwa, genus 

 Nanina of that author's classification. Indeed ou*' figure of 

 the lingual dentition of Nanina cabias, Benson (Am. Jour, 

 of Conch, vii, pi. 17, fig. 6), almost equally well applies to 

 the species under consideration, as will be seen from the 

 following description of their dentition. 



The jaws stout, arcuate, high, ends slightly attenuated, 

 blunt ; anterior surface with no ribs ; cutting edge with a 

 decided, blunt, median projection. , 



Lingual membrane long, I)road. Central and lateral teeth 

 in horizontal rows, in shape as usual in the Helicidm. Mar- 

 ginal teeth in oblique rows, aculeate, bluntly bifid, decreas- 



