We present our determination of the nuclear supermassive black hole mass ( SMBH ) function for spiral galaxies in the local universe , established from a volume-limited sample consisting of a statistically complete collection of the brightest spiral galaxies in the southern ( \delta < 0 ^ { \circ } ) hemisphere . Our SMBH mass function agrees well at the high-mass end with previous values given in the literature . At the low-mass end , inconsistencies exist in previous works that still need to be resolved , but our work is more in line with expectations based on modeling of black hole evolution . This low-mass end of the spectrum is critical to our understanding of the mass function and evolution of black holes since the epoch of maximum quasar activity . A limiting luminosity ( redshift-independent ) distance , D _ { L } = 25.4 Mpc ( z = 0.00572 ) and a limiting absolute B -band magnitude , \mathfrak { M } _ { B } = -19.12 define the sample . These limits define a sample of 140 spiral galaxies , with 128 measurable pitch angles to establish the pitch angle distribution for this sample . This pitch angle distribution function may be useful in the study of the morphology of late-type galaxies . We then use an established relationship between the logarithmic spiral arm pitch angle and the mass of the central SMBH in a host galaxy in order to estimate the mass of the 128 respective SMBHs in this volume-limited sample . This result effectively gives us the distribution of mass for SMBHs residing in spiral galaxies over a lookback time , t _ { L } \leq 82.1 h _ { 67.77 } ^ { -1 } Myr and contained within a comoving volume , V _ { C } = 3.37 \times 10 ^ { 4 } h _ { 67.77 } ^ { -3 } Mpc ^ { 3 } . We estimate that the density of SMBHs residing in spiral galaxies in the local universe is \rho = 5.54 _ { -2.73 } ^ { +6.55 } \times 10 ^ { 4 } h _ { 67.77 } ^ { 3 } M _ { \odot } Mpc ^ { -3 } . Thus , our derived cosmological SMBH mass density for spiral galaxies is \Omega _ { BH } = 4.35 _ { -2.15 } ^ { +5.14 } \times 10 ^ { -7 } h _ { 67.77 } . Assuming that black holes grow via baryonic accretion , we predict that 0.020 _ { -0.010 } ^ { +0.023 } h _ { 67.77 } ^ { 3 } \permil of the universal baryonic inventory ( \Omega _ { BH } / \omega _ { b } ) is confined within nuclear SMBHs at the center of spiral galaxies .