Can't say about whether it was left out or not, but the sixth house, the first one missing (and saying sixth house reminds me of Morrowind so much) is the house of the leffit.
House of the Leffit: the house of the leffit is the house of Connections, it deals with relationships, love, romance, family. Personal connections.
Zodiac can be found here, so you should be able to find which other one you're missing there.
Edit because I can't seem to figure it out myself. Probably because I'm tired.
Edit 2: or because it's actually missing one house
The missing house, according to this thread is the house of the wildcat.