the two last moons discovered in orbit around Pluto in 2011 and 2012 by the +Hubble Space Telescope, has firstly called by numerical identifiers, respectively P4 and P5. Actually, in astronomy, naming of planets go to the finders and in this case, that honor went to a scientific team led by +Mark Showalter a researcher at the +SETI Institute in Mountain View, California.
After a online vote, many fans of +Star Trek proposed the name of Vulcan, the name of Spock's home planet. However, the International Astronomical Union (IAU) rejected this proposition. Actually, Vulcan was the name given to a hypothetical planet astronomers thought they had discovered between the Sun and Mercury back in the 1800s.
Finally, the two Pluto's moons will be called Kerosene and Styx, two names of the roman and greck mythology.