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Maintenance-mode feedback from low-accretion rate AGN, manifesting itselfobservationally through radio-loudness, is invoked in all cosmological galaxyformation models as a mechanism that prevents excessive star-formation inmassive galaxies (M$_*$ $\gtrsim$ 3$\times$10$^{10}$ M$_{\odot}$). Wedemonstrate that at a fixed mass the incidence of radio-loud AGN (L $>$10$^{23}$ WHz$^{- 1}$) identified in the FIRST and NVSS radio surveys among alarge sample of quiescent (non-star forming) galaxies selected from the SDSS ismuch higher in geometrically round galaxies than in geometrically flat,disk-like galaxies. As found previously, the RL AGN fraction increases steeplywith stellar velocity dispersion $\sigma_*$ and stellar mass, but even at afixed velocity dispersion of 200-250 kms$^{-1}$ this fraction increases from0.3% for flat galaxies (projected axis ratio of q $<$ 0.4) to 5% for roundgalaxies (q $>$ 0.8). We rule out that this strong trend is due to projectioneffects in the measured velocity dispersion. The large fraction of radio-loudAGN in massive, round galaxies is consistent with the hypothesis that such AGNdeposit energy into their hot gaseous halos, preventing cooling andstar-formation. However, the absence of such AGN in disk-like quiescentgalaxies -- most of which are not satellites in massive clusters, raisesimportant questions: is maintenance-mode feedback a generally valid explanationfor quiescence; and, if so, how does that feedback avoid manifesting at leastoccasionally as a radio-loud galaxy?

An Absence of Radio-Loud Active Galactic Nuclei in Geometrically Flat Quiescent Galaxies: Implications for Maintenance-Mode Feedback Models