Method to subtract a List from another

I'm trying scala after a long time, so this may be an easy question:

$ scala
Welcome to Scala version 2.7.0-final (Java HotSpot(TM) Client VM, Java 1.6.0_07)
.
Type in expressions to have them evaluated.
Type :help for more information.

scala> List(1,2,3,4)
res0: List[Int] = List(1, 2, 3, 4)

scala> List(2,3)
res1: List[Int] = List(2, 3)

scala> res0 -- res1
<console>:7: error: value -- is not a member of List[Int]
       res0 -- res1
            ^


Regards,
aMit