42 i Bemarhs on Certain Species 



sualljlarge specimen, said to be from Tennessee, I am indebted 

 to Mr. Ilenrj Van Kostrand ; it measures, 



Diam. maj. 23, min. 19, Alt. 9 mill. (0 whorls). 



The comparatively smooth Ohio form is, 



Diam. maj. 19, min. 16, Alt. Y mill. (5^ whorls). 



A small variety from Goat Island, IST. Y., is, 



Diam. maj. 18, miii. 10|, Alt. h\ mill (5 whorls). 



A variety found by Mr, IT. Yan ISTostrand, at Delaware 

 Water Gap, Pa., has v^xj rigid somewhat distant, ribs. 



The position of the upper lip-tooth in this species is not abso- 

 lutely constant, its distance from the lower one is variable. 



Helix triodoiatoides nov. §i>. 



Plate lY fig. 11-12. 



T. perforata, globoso-depressa, tenui, subpellucida, pallidc cornea, 

 superne subobsolete costulato-striata, basi convexa, laevigata, ; spirS, 

 brevi ; anfr. 5 convexiusculis, ultimo prope apertnram plicato, antice 

 deflexo ; apertiira rotniidato-lunari, obliqna, coarctata ; perist. reflexo, 

 calloso, margiiiibus deiite liiiguifonni, acute, triangulari junctis, dextro 

 dente in inargiiie calli posito, basali dente obliquo nuinito, ambobus den- 

 tibus parvis, inter se remotis. 



Shell perforate, globose-depressed, thin, subpellucid, pale 

 horn-colored, with partially obsolete rib-like strise above ; base 

 convex, smooth ; spire short; whorls 5, somewhat convex, the 

 last plicately ribbed near the aperture, deflexed anteriorly ; 

 aperture roundly lunate, oblique, contracted ; perist. reflected, 

 callous, the margins joined by a sharp linguiform ti-iangular 

 tooth, the right with a tooth on the margin of the callus, 

 basal witli an oblique tooth, both teeth small and far ai3art. 



Diam. maj. 9^, min. 8, Alt. 5 mill. 



Habitat. — De Witt Co., Texas, Dr. E'ewcomb ! ; Corpus 

 Christi, Texas. 



liemarhs. — It has been generally assumed that the H. trio- 



