PILSBRY: non-marine MOLLUSCA of PATAGONIA. 613 



those which appear to have radiated from the Antillean Continent are 

 indicated by the letter A. 



Uiiioiiicicu, Mcgaspiyidcp, 



Pleuroceratidcc, Urocoptidce A, 



Vivipayidce, Testacellidce, 



Diplouiniatiiiidcv, Zonitidcc, ^ 



Cyclostomatidcu A, Lhiiacidcr, 



Proserpitiidce A, Arionidce, 



LyjuncriiicB, P/ii/oinycidce, 



He/icidce, Oleaciiiidcs A. 



Clausiliidce, 

 III. Eogceic or Sottthcni fauna, which occupied chiefly the Gondwana 

 continent, including a large part of South America, tropical and south 

 Africa, and stretching in a great arch, possibly at no time perfect, to penin- 

 sular India and Australia. Here were evolved the families : 



Mutelidce. AchaiinidcE. 



EtJieriidcc. AperidcE. 



Anipiillayiidce. Rhytidida;. 



Chilinidce. Streptaxidce. 



Aca'vid(^. Circmarndcs. 



Strophocheilidce. VeronicellidcB. 



Bulwudidce. 

 The South American fauna is largely made up of groups of typically 

 Eogaeic or Southern origin, but there are also northern forms, derived 

 from Middle America (" Antillia "), and a few groups of ancient and 

 unknown origin. These several elements are as follows. 



I. Primitive Group. 



Families of very Ancient and Unknown Origin and World-ivide Distribu- 

 tion, and Isolated Autochthonous Families of Eogceic Origin. 

 CircinariidcB. Northern South America and temperate North America. 

 Bulimulidce. Autochthonous ; formerly spread to Australasia and now 



invading North America. 

 Strophocheilidce . Autochthonous. 

 EndodontidcB. World-wide, on all continents and islands. 



' Primitive Zonitidit were probably evolved at a very early time, but the group attained its main 

 development in the Csenogaeic faunas. 



