NEW FRESH-WATER SHELLS FROM GUATEMALA. 



By William B. Marshall. 



Assistant Curator, Division of Marine Invertebrates, United States National Museum. 



The United States National Museum's rather extensive collection 

 of the genus SpTiaeromelania has recently been enriched by a fine 

 series of specimens from Guatemala, collected and presented by Mr. 

 Anson A. Hinkley, of Du Bois. Illinois. Among these is one lot of 

 specimens which do not agree with any in the collection nor with any 

 described species so far as I have been able to determine. Knowing 

 that the species of Sjiihaeromelania are subject to great variation, as 

 great, perhaps, as is to be found in the v/hole molluscan realm, I 

 have been unusually cautious and have carefully considered all the 

 evidence available before coming to the decision that these shells 

 belong to a new species. 



The new species of CocMiopa here described is very different from 

 any previously known species. The shell of this species so intimately 

 resembles Valvata that it would be placed in that genus were it not 

 for the operculum. 



SPHAEROMELANIA HINKLEYI, new species. 



Plate 17, figs. 4-13. 



Shell bulimiform, denselj" spirally striated, obsoletely malleated. 

 Axial sculpture consisting of numerous fine growth lines, with an occa- 

 sional rest period accentuated, especially on the body whorl just be- 

 hind the aperture. Whorls (apical ones lost) apparently about seven, 

 moderately rounded, rapidly enlarging, the body whorl forming about 

 two-thirds of the shell. Suture well impressed. Color nearly uni- 

 form, dark chestnut. Aperture pyriform, columellar lip with a heav}^ 

 deposit of callus, especially at its upper end, deeply sinuate near its 

 lower end, its prevailing color dark purplish brown, pale on its inner 

 edge. Interior of shell pale livid purplish with a vertical blackish 

 stripe near the outer lip. Outer lip simple, margined with blackish. 



The type (fig. 6), Cat. No. 336412, U.S.X.M., measures— length, 

 37.5 mm.; greater diameter, 21.5 mm.; lesser diameter, 19 mm. It 

 and 15 other specimens were presented by Mr. Hinkley, who collected 

 them in the Tsalbha River at Chama, Alta Vera Paz, Guatemala, in 

 February, 1917. 



Proceedings U. S. National Museum. Vol. 58-No. 2336. 



301 



