  We present a theory of spinor superfluidity in a two-species heteronuclear
ultracold fermionic atomic gas consisting of arbitrary half-integer spin and
one-half spin atoms. In particular, we focus on the magnetism of the superfluid
phase and determine the possible phases in the absence of a magnetic field. Our
work demonstrates similarities between heteronuclear fermionic superfluids and
spinor Bose-Einstein condensates at the mean-field level. Possible experimental
situations are discussed.
