We present kinematics and stellar population properties of 17 dwarf early-type galaxies in the luminosity range -14 \geq M _ { B } \geq - 19 .
Our sample fills the gap between the intensively studied giant elliptical and Local Group dwarf spheroidal galaxies .
The dwarf ellipticals of the present sample have constant velocity dispersion profiles within their effective radii and do not show significant rotation , hence are clearly anisotropic .
The dwarf lenticulars , instead , rotate faster and are , at least partially , supported by rotation .
From optical Lick absorption indices , we derive metallicities and element abundances .
Combining our sample with literature data of the Local Group dwarf spheroidals and giant ellipticals , we find a surprisingly tight linear correlation between metallicity and luminosity over a wide range : -8 \geq M _ { B } \geq - 22 .
The \alpha / { Fe } ratios of our dwarf ellipticals are significantly lower than the ones of giant elliptical galaxies , which is in agreement with spectroscopy of individual stars in Local Group dwarf spheroidals .
Our results suggest the existence of a clear kinematic and stellar population dichotomy between dwarf and giant elliptical galaxies .
This result is important for theories of galaxy formation , because it implies that present-day dwarf ellipticals are not the fossiled building blocks of giant ellipticals .