310 MEXICAN LEPTINARIA. 



5, rather convex, suture compressed, the upper whorls dis- 

 tinctly costulate, the last whorl well rounded at the base. 

 Aperture moderately oblique, trapezoidal-piriform, the outer 

 margin moderately arcuate, not arched forward, basal margin 

 rather narrowly rounded; columellar margin broadly dilated 

 above, narrowed towards the base, slightly twisted; parietal 

 wall without callus. Length 5, diam. 3, aperture 3x2 mm. 

 (Marts.). 



Mexico: Teapa, Tabasco (H. H. Smith). 



L. exigua MAETS., Biologia, p. 318, pi. 18, f. 10 (1898). 

 "Distinct from L. guatemalensis Or. & Fiseh., and from L. 

 martensi var. inflata, by the want of costse on the last whorl 

 and by the size. Both the sculpture and the columellar fold 

 are very feebly developed, but the general appearance of 

 the shell is that of a true Leptinaria. The two specimens 

 seen are of equal size. The whorl before the last in one of 

 them is distinctly costate, in the other with obsolete costae. 

 Both shells have somewhat the aspect of not being full-grown, 

 but I know no other species to which they could be attributed 

 as a young state" (von Martens). 



23. L. INTERSTRIATA (Tate). PI. 41, fig. 12. 



Shell openly perforate, ovate-conic, thin; sculptured with 

 slender, well-spaced, slightly arcuate riblets, which disappear 

 at the periphery of the last whorl and are wanting on the 

 initial 2 1 / 4 whorls; the intervals weakly striatulate. Whit- 

 ish-corneous (but no quite fresh shells were taken). Spire 

 straightly conic, the summit obtuse ; whorls Q l / 2 , strongly con- 

 vex, parted by a deep suture, the base of the last whorl quite 

 convex. Aperture ovate, scarcely oblique, the outer lip evenly 

 arcuate, very little arched forward. Columellar margin 

 widely dilated above, rapidly tapering downward, bearing a 

 very strong, obtuse, spiral lamella near its base, concave and 

 oblique above the lamella. No parietal lamella. 



Length 7.5, diam. 3.5 mm., aperture 3 mm. (co-type). 



Length 9.37, diam. 4.37 mm., whorls 7 to 8 (Tate, co-type). 



Panama : On an island in the lagoon of Boca del Toro 

 (Tate). Costa Rica: Plains of the Rio Grande of Terraba 

 (Pittier). 



