560 PATAGONIAN EXPEDITIONS I ZOOLOGY. 



lar posteriorly. Streams in the pampas south of Buenos Aires as 

 far as Bahia Blanca, especially in the Rio Salado and Arroyo Salado 

 in 30 S. lat. Hydrobia parchappii 'Doering, Bol. Acad. Cienc. Cor- 

 doba, VII, 472. 



LITTORIDINA KUESTERI (Strobel). Hydrobia kiisteri Strobel, Mater. 

 Malac. Argent, 1874, p. 61, pi. 2, fig. 6. 4X2.5 mm., 5 whorls, 

 to 3.5 X 2-2.5 mm. San Carlos ed Aguanda, province of Mendoza, 

 in stagnant water. Hydrobia kusteri var. cordillerce Strobel, t. c., 

 p. 61, pi. 2, fig. 7. 3X1.5-2.5X1.33 mm -> 4> whorls. Sierra 

 de Mendoza. 



LITTORIDINA AMEGHINI (Doering). Hydrobia ameghini Doering, Bol. 

 Acad. Cienc. Cordoba, VII, pp. 466, 469. 7-9X3.5-4 mm., whorls 

 75^ . Pampean formation, Lujan, Argentina. 



LITTORIDINA OCCIDENTALIS (Doering). Hydrobia occidentalis Doering, 

 t. c., pp. 466, 471. 6x2.7 mm., whorls 6. San Luis, Mendoza, 

 San Juan, Santiago, Argentina. 



LITTORIDINA MONTANA (Doering). Hydrobia montana Doering, t. c., 

 pp. 467, 473. 4.5 x 2 mm., whorls 6. Sierras de Cordoba and S. 

 Luis, Argentina. 



LITTORIDINA GLABRA (Tryon). Hydrobia glabra Tryon, American Jour- 

 nal of Conchology, I, p. 222, pi. 22, f. 12. Bolivia. 



LITTORIDINA CUMINGII (d'Orbigny). Pahidina cumingii d'Orb., Mag. de 

 Zool., 1835, p. 30. Paludestrina cumingii d'Orb., Voy., p. 385, pi. 47, 

 figs. 14-16. 6X2 mm., whorls 6. In fresh-water streams near 

 Callao and at Valparaiso. 



LITTORIDINA ATACAMENSIS (Philippi). Paludina atacamensis Philippi, 

 Reise durch die Wiiste Atacama, 1860, p. 185, Taf. 7, fig. 15. Length 

 \\ lines, whorls 5. Tilopozo, Chili, in about 23, 20' S. lat. 



LITTORIDINA POPOENSIS (Bavay). Paludestrina popoensis Bavay, Bull. 

 Soc. Zool. France, 1904, p. 154, fig. 5. Conic, 5X2.5-3.5 mm., 

 with 6 to 7 rounded whorls. Lake Popo, Bolivia. 



LITTORIDINA CUZCOENSIS n. sp. (figs. 10, 11). The shell is minutely 

 perforate or rimate, thin, corneous-white, smooth and glossy. Spire 

 straightly conic, whorls 6, moderately convex, the last evenly rounded. 

 Aperture ovate, slightly oblique. Peristome thin and simple. 



Fig. 10. Length 4.9, diam. 2.5, length of aperture 1.8 mm. (typical). 

 " ii. " 4.8 " 2.2 " " 1.6 " (slender phase). 



