THREE NEW LAND SHELLS FROM MEXICO AND 



GUATEMALA. 



By Paul Bartsch, 



Assistant Curator, Division of Mollusks, U. S. National Museum. 



Among the mollusks collected by Messrs. E. W. Nelson and E. A. 

 Goldman in Mexico and H. Pittier in Guatemala are several new 

 forms which are characterized below. 



EUGLANDINA NELSONI, new species. 

 Plate 33, figs. 1, 3, 4, G. 



Shell elongate, ovate, semitranslucent, light horn yellow. Nuclear 

 whorls, two and one-half, smooth. Post-nuclear whorls slightly 

 rounded, appressed at the summit, marked by numerous slender, 

 slightly retractive axial riblets which are about as wide as the shallow 

 spaces that separate them. These riblets are strongest near the 

 suture which they render feebly crenulate, and least developed on the 

 base. There is no indication of spiral sculpture. Sutures well 

 marked. Outer lip of aperture sigmoid in outline, the middle portion 

 being built out; columella evenly, gently curved. 



There are four specimens of this species before me, cotypes (Cat. No. 

 207784 U.S.N.M.), collected by Nelson and Goldman at Acaponeta, 

 Tepic, Mexico. They vary considerably in size and outline. 



The following table gives their measurements : 



a The length of aperture is taken from the posterior angle to the most anterior point of the outer lip. 



Named for E. W. Nelson. 



Proceedings U. S. National Museum, Vol. 37— No. 1707. 

 Proc.N.M.vol.37— 09 21 



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