In this paper, we present a new blind and robust 3-D mesh watermarking scheme that makes use of the recently proposed manifold harmonics analysis. The mesh spectrum coefficient amplitudes obtained by using this analysis are quite robust against various attacks, including connectivity changes. A blind 16-bit watermark is embedded through an iterative scalar Costa quantization of the low frequency coefficient amplitudes. The imperceptibility of the watermark is ensured since the human visual system has been proved insensitive to the mesh low frequency components modification. The embedded watermark is experimentally robust against both geometry and connectivity attacks. Comparison results with two state-of-the-art methods are provided.