Intrathermocline anticyclonic eddies of Mediterranean origin(meddies)are regularly met in the Eastern part of the Atlantic Ocean.These vortices are identified both from a satellite as changes in altimetry and temperature of the ocean surface,and according to the neutral buoyancy floats(NBF),placed in the lens body.In this paper,in the framework of a three-layer quasi-geostrophic model,using the method of contour dynamics,we consider some theoretical aspects of lens movements,observed by acoustic NBF and freely drifting buoys of the Project Argo.These direct experimental observations of the lenses drift in the North Atlantic qualitatively confirmed the results of our numerical experiments.In particular,it is shown that the lens spin has an advective influence on the behavior of NBF at distances of several lens radii.