The observations made during one unusual crossing of the magnetopause by the satellite Ogo 5 are compared with the classical reconnection model developed by Levy, Petschek, and Siscoe. The magnetic field observations appear to be generally consistent with this MHD model, although allowance must be made for the fact that the estimated magnetopause thickness was no more than 3.5 ion gyrodiameters. The nature of the finite gyroradius effects in such thin structures is discussed.