  A list of the Castor stream members is compiled based on the data from
various authors. The membership probabilities for some stars are revised based
on the individual apex, multiplicity, observational errors, and peculiarity.
The apex of the Castor moving group is determined using the apex diagram
method. The parameters of the Castor and Ursa Major streams are compared and
the positions of the two streams on the apex diagram are found to differ by
225deg, implying that the two groups move in almost opposite directions. Stars
of both moving groups are intermixed in space, the Castor stream occupies a
smaller volume than the UMa stream and is located inside it. Our results can be
useful for understanding the morphology of the Galactic disk in the Sun's
vicinity.
