  We present photometry of nine cataclysmic variable stars identified by the
Sloan Digital Sky Survey, aimed at measuring the orbital periods of these
systems. Four of these objects show deep eclipses, from which we measure their
orbital periods. The light curves of three of the eclipsing systems are also
analysed using the LCURVE code, and their mass ratios and orbital inclinations
determined. SDSS J075059.97+141150.1 has an orbital period of 134.1564 +/-
0.0008 min, making it a useful object with which to investigate the
evolutionary processes of cataclysmic variables. SDSS J092444.48+080150.9 has a
period of 131.2432 +/- 0.0014 min and is probably magnetic. The white dwarf
ingress and egress phases are very deep and short, and there is no clear
evidence that this object has an accretion disc. SDSS J115207.00+404947.8 and
SDSS J152419.33+220920.1 are nearly identical twins, with periods of 97.5 +/-
0.4 and 93.6 +/- 0.5 min and mass ratios of 0.14 +/- 0.03 and 0.17 +/- 0.03,
respectively. Their eclipses have well-defined white dwarf and bright spot
ingress and egress features, making them excellent candidates for detailed
study. All four of the orbital periods presented here are shorter than the 2-3
hour period gap observed in the known population of cataclysmic variables.

Solar and Stellar Astrophysics