100 GASTROCOPTA, SOUTH AMERICA. 



The specimens from Abingdon (pi. 19, figs. 12-14) agree 

 with the typical description and figure (fig. 9). The last 

 two whorls are rather weakly convex. There seems to be little 

 if any crest behind the lip, which expands narrowly. The 

 angular and parietal lamellae are well separated, much as in 

 G. bilamellata, and more than in any nearly related species; 

 but the inner end of the parietal does not curve towards the 

 periphery, as in the Immersidens group. The infraparietal 

 lamella is laminiform and runs inward parallel to the parietal. 

 Columellar lamella is very strong and the callous below it is 

 built up into a subcolumellar lamella. The lower palatal 

 plica enters deeply. Upper palatal plica is strong but shorter. 

 A thin interpalatal stands between them. Basal plica well 

 developed, entering. The peristome, as in G. munita, is 

 strongly labiate or calloused within except at the sinulus. 



Length 2.1, diam. 0.9 mm. 



Length 2.2, diam. 1 mm. 



While related to G. munita, this is an extremely distinct 

 species, recalling the West-Indian G. polyptyx and the Bonin 

 Island species. 



Subgenus IMMERSIDENS Pils. 

 34. GASTROCOPTA DICRODONTA (Doering). 



' * Shell minute, pupoid, smooth, substriatulate, a little shin- 

 ing, brownish-corneous. Spire subconic, the summit tapering, 

 rather obtuse. Whorls 5% to 6, a little convex, the last about 

 two-fifths the length. Aperture oval-rounded, contracted by 

 5 (-6) teeth: the first, on the parietal wall, largest, twisted, 

 bifid (forked or biramose), the right branch produced to the 

 margin of the peristome, the other remote from the margin 

 of the aperture ; second tooth columellar, tortuous, angulate, 

 lengthened within; three pliciform palatal teeth. Peristome 

 expanded, scarcely reflected, whitish, the margins nearly con- 

 nected, right margin curved. Length 1.8 to 2, width 0.9 mm. ; 

 aperture 0.7 to 0.8 mm. long" (Doering). 



Argentina: around Villa Vicencio in the Sierra de Men- 

 doza; all suitable places in the sierras of Cordoba and San 

 Luis (Dr. Stelzner). 



