APPROXIMATE ROUTES TRAVERSED BY THE HELICIDA^ AND OTHER ORGANISMS 
FROM THE I-KOBAIiLE EVOLUTIONARY CENTRE, WHICH HAVE LED TO THE UNIVERSAL DISPERSAL OF LiFE OVER THE GlOBE. 
Plate III. 
. ^he stronger U’aves Represent the hfiain courses of the tnigratoty stream \ the closer rippling indicates the relative slowness of the advance. 
