558 PATAGONIAN EXPEDITIONS I ZOOLOGY, 



LITTORIDINA CHARRUANA (d'Orbigny). 



(Plate XLk, Figs, i, 2.) 



Paludestrina charruana d'Orb., Voy., p. 384, pi. 75, figs, i, 2 (at the 

 embouchure of a stream into the sea north of Montevideo) ; ' von 

 Ihering, Nachrbl., 1895, p. 123, anatomy (Iguape, Sao Paulo). 

 A shorter, stouter snail than L. australis, the cuticle olive, with black 

 growth-arrest lines in old shells. It varies widely in shape, as may be 

 seen by figs, i, 2, which represent average, stout and slender shells from 

 the Rio Cubatao, near Santos, State of Sao Paulo. They measure : 

 Length 5.8, diam. 3.5, aperture 2.6 mm.; whorls 6. 



5-7 " 3-i " 2.5 " " 7. 



2.7 2.2 



It has also been sent by Dr. von Ihering from the Ribeira at Iguape 

 and from Guatzbu, State of Rio Grande do Sul, where the shells are more 

 slender. 



d'Orbigny's type measured, length 5, diam. 3 mm., whorls 6. 



LITTORIDINA PICIUM (d'Orbigny). 



(Plate XLLr, Fig. 13.) 



Paludina picium d'Orb., Mag. de Zool., 1835, p. 30. 

 Paludestrina picium d'Orb., Voyage, p. 383, pi. 47, figs. 17-21 (Rio de La 

 Plata at Buenos Aires, etc., under stones); von Ihering, Nachrbl., 

 1895, p. 123, anatomy (Rio Grande do Sul); von Martens, Malak. 

 Blatter, XV, 1868, p. 192 (Rodersberg). 



This is smaller and thinner than L. charruana, less opaque, of a paler 

 greenish yellow or olive-corneous tint. The whorls are rather strongly con- 

 vex, the suture well-impressed, having a grayish border below. d'Orbigny 

 gives the size as length 3, diam. 2 mm., whorls 5. Two from San 

 Gabriel's Island, in the Rio de La Plata off Colonia, Uruguay, measure: 



Length 4, diam. 2.2, aperture 1.8 mm.; whorls 6. 

 Fig. 13. 4 2.4 " 1.8 " SH- 



Specimens are before me also from the type locality, Buenos Aires, 

 agreeing fully with those figured. 



Littoridina glabra (Tryon) from Bolivia resembles L. piciitm, but it is 

 somewhat more slender, thinner, the columella less calloused. 



