  We extend results first announced by Franz et al. (1998), that identified vA
351 = H346 in the Hyades as a multiple star system containing a white dwarf.
With Hubble Space Telescope Fine Guidance Sensor fringe tracking and scanning,
and more recent speckle observations, all spanning 20.7 years, we establish a
parallax, relative orbit, and mass fraction for two components, with a period,
$P=2.70$y and total mass 2.1 Msun. With ground-based radial velocities from the
McDonald Observatory Otto Struve 2.1m telescope Sandiford Spectrograph, and
Center for Astrophysics Digital Speedometers, spanning 37 years, we find that
component B consists of BC, two M dwarf stars orbiting with a very short period
(P_ BC=0.749 days), having a mass ratio M_C/M_B=0.95. We confirm that the total
mass of the system can only be reconciled with the distance and component
photometry by including a fainter, higher mass component. The quadruple system
consists of three M dwarfs (A,B,C) and one white dwarf (D). We determine
individual M dwarf masses M_A=0.53+/-0.10 Msun, M_B=0.43+/-0.04Msun, and
M_C=0.41+/-0.04Msun. The WD mass, 0.54+/-0.04Msun, comes from cooling models,
an assumed Hyades age of 670My, and consistency with all previous and derived
astrometric, photometric, and RV results. Velocities from H-alpha and He I
emission lines confirm the BC period derived from absorption lines, with
similar (He I) and higher (H-alpha) velocity amplitudes. We ascribe the larger
H-alpha amplitude to emission from a region each component shadows from the
other, depending on the line of sight.
