318 MEXICAN LEPTINARIA. 



Columellar margin a little thickened t>asally, arcuate, dis- 

 tinctly twisted and toothed in the middle, thick above, dilated, 

 lightly concave. Parietal wall with hardly any callus. 

 Length 11, diam. 4, aperture 3.75x2.33 mm. (Marts.). 



Costa Rica: plains of the Rio Terraba, 20 meters above 

 the sea (Pittier). 



L. hapaloides MARTS., Biologia, p. 321, pi. 18, f. 16 (Oct., 

 1898). 



"Very distinct on account of the elongated form and the 

 arcuated folds" (of the surface). 



36. L. AMBIGUA Martens. PI. 42, fig. 22. 



Shell oblong-turrite, rather widely rimate, lightly and 

 evenly striatulate, somewhat glossy, pale yellowish, the apex 

 obtuse. Whorls 7, rather flat, equally and slowly increasing, 

 the suture moderately impressed; last whorl convexly taper- 

 ing basally. Aperture a little oblique, piriform, the outer 

 margin slightly arcuate, slightly arched forward, basal mar- 

 gin narrowly rounded. Columellar margin obliquely trun- 

 cate at the base and encircled with a thin, slender, spiral fold, 

 then a little concave; above being slightly dilated and ap- 

 pressed. Parietal wall slightly calloused, unarmed (Marts.). 



Length 11, diam. 3.75 to 4, aperture 3.25 x 2 mm. 



Length 10, diam. 3.5, aperture 3x2 mm. 



Length 9, diam. 4, aperture 3x2 mm. 



Costa Rica: Puerto Viejo, at the confluence of the Puerto 

 Vie jo and Sarapiqui rivers (Biolley) ; La Palma (Pittier). 



L. ambigua MARTS., Biologia, p. 321, pi. 18, f. 17 (Oct., 

 1898). 



"This species at first sight more resembles an Opeas than 

 a Leptinaria, on account of its general form and the want of 

 prominent costse; the columellar margin, however, is not 

 only obliquely notched, but has a slender spiral fold twisted 

 round its lowest part and clearly separated from it by a slen- 

 der furrow. This fold is also very much nearer the base of 

 the aperture than in the other species of Leptinaria" (Mts.). 



37. L. SOLIDA Martens. PI. 42, fig. 37. 



Shell conoidal-ovale, half-openly perforate, rather solid, 



