PILSBRY: NON-MARINE MOLLUSCA OF PATAGONIA. 545 



Duplicaria bonariensis Rafinesque, Atlantic Journal and Friend of Knowl- 

 edge, No. V, 1833, p. 165; Binney and Tryon's reprint, p. 93. 

 A short-oval, inflated shell, with usually olive ground-color, but some- 

 times olive-yellow or bright green, and either unicolored or marked with 

 one to five spiral bands of dark chestnut spots, alternating with spots paler 

 than the ground-color. The upper bands are more persistent than those 

 below. Very rarely the pattern is of irregularly zigzag streaks flowing 

 from the suture down, not quite reaching the base (fig. 38). The ample 

 aperture is blue-white within, and usually shows the external markings 

 through. The columellar lamella is very strong, and a long entering callous 

 ridge stands on the parietal wall, and is always well developed in adult 

 snails. The specimens figured from San Gabriel's Island, opposite 

 Colonia, Uruguay, measure : 



Fig. 35. Length 11, diam. 7.9, length of aperture 8.9 mm. 



" 36. " 10.25, " 7 " " 8.25 " 



" 37. " 12 " 8.5 " " 9.9 



" 38. " 10.8 " 7.5 " " 9 



" 39. " 7.8 " 5.6 " " 6.8 " 



Some examples from Buenos Aires are larger, 13.25 mm. long. All 

 adult shells s.een have the spire eroded. 



Fig. 36 has the pattern of the type of C. fltmiinea. Fig. 35 is the 

 color-form which Maton called fluviatilis, but it has no racial characters. 1 

 Figures 38 and 39 are color-forms hitherto unrecorded. The spots com- 

 posing the bands vary in size, and are sometimes reduced to mere dots. 



Very young shells, 2.25 mm. long, are plain colored, have no parietal 

 fold, and only a very small columellar fold. With growth, the band at 

 the shoulder appears first. No streaked stage precedes the bands. 



La Plata (Maton); Buenos Aires (Phila. Acad. coll.); San Gabriel's 

 Island (Dr. W. H. Rush); Rio Colorado (Roca Exped.). 



CHILINA FLUMINEA MICRODON subsp. nov. 



(Plate XLV, Figs. 40-44.) 



Chilina fluminea d'Orb., Heynemann, Malak. Blatter, XV, 1868, p. 112, 



Taf. 5, fig. 1 1 (teeth). 

 Chilina flwninea Maton, Martens, t. c., p. 184. 



'The name Valuta fluviatilis has precedence on Maton's page, but subsequent authors have 

 preferred that of fluminea. 



