PILSBRY : NON-MARINE MOLLUSCA OF PATAGONIA. 533 



The eastern fauna, with which alone we have now to deal,^ inhabits a 

 comparatively arid region, poorly watered by roughly parallel streams 

 flowing southeastward into the Atlantic. Each of the principal river 

 systems has its own series of freshwater mollusks, in large part distinct 

 specifically or racially from those of other rivers. The Cliili)iidcc of the sev- 

 eral drainages have been enumerated on pp. 514-5. 



Chilina patagonica Sowerbv. 



Chilina patagonica Sowb., Conchologia Iconica, XIX, pi. 3, fig. 1 1 (bad), 

 August 1874; E. A. Smith, Proc. Zool. Soc, London, 1881, p. 845; 

 Strebel, Zool. Jahrb., XXV, 1907, p. 166. 



Patagonia (Sowerby). Puerto Bridges, Picton Island and Puerto 

 Montt (Strebel, various forms taken by Michaelson and Lau). 



Mr. Smith has given valuable information on this species in his paper 

 of 1 88 1. Strebel includes in it some very diverse forms, the pertinence 

 of which to patagonica seems open to doubt. 



The specimens figured by Strebel from Gente Grande Bay, under the 

 name ''Chilina flnviatilis Gray," are obviously not Chilina Jlnviatilis 

 (Maton) of the La Plata drainage. What they are, remains uncertain. 



Chilina amcena E. A. Smith. 



Chilina amcena E. A. Smith, P. Z. S., 1881, pp. 37, 846, pi. 4, f. 18, i8(7. 



" This species is remarkable for its fragility, the slenderness of its form 

 and the vividness of the markings." 



Length 26, diam. 11, aperture 14.5 mm. 



Tom Bay (Coppinger). 



Chilina fuegiensis E. A. Smith. 



Chilina fuegiensis E. A. Smith, Proc. Malac. Soc. London, VI, p. 339, 

 fig. vii, September, 1905. 



A very slender species, length 24, diam. 10, aperture 13.5 mm., appar- 

 ently related to the preceding. 



Rio Marazzi, Useless Bay, Tierra del Fuego. 



' Mr. E. A. Smith has pubhshed a catalogue of Chilina in Proceedings of the Zoological Society 

 of London, 1881, to which the student is referred for information on the species of Chili. 



