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We present spectroscopy and orbital periods Porb for 30 apparentlynon-magnetic cataclysmic binaries with periods below about 3 hours, nearly allof which are dwarf novae, mostly of the SU Ursae Majoris subclass. We then turnto the evidence supporting the prediction that short-period dwarf novae evolvetoward longer periods after passing through a minimum period -- the "periodbounce" phenomenon. Plotting data from the literature reveals that forsuperhump period excess $\epsilon = (P_{\rm sh} - P_{\rm orb} )/P_{\rm orb}$below about 0.015, the period appears to increase with decreasing epsilon,agreeing at least qualitatively with the predicted behavior. Next, motivated bythe long (decadal) outburst intervals of the WZ Sagittae subclass ofshort-period dwarf novae, we ask whether there could be a sizable population of"lurkers" -- systems that resemble dwarf novae at minimum light, but do notoutburst over accessible timescales (or at all), and therefore do not drawattention to themselves. By examining the outburst history of the Sloan DigitalSky Survey sample of CVs, which were selected by color and not by outburst, wefind that a large majority of the color-selected dwarf-nova-like objects havebeen observed to outburst, and conclude that "lurkers", if they exist, are arelatively minor part of the CV population.

Spectroscopic Studies of 30 Short-period Cataclysmic Variable Stars, and Remarks on the Evolution and Population of Similar Objects