diff --git a/akka-stream/src/main/scala/akka/stream/Stream.scala b/akka-stream/src/main/scala/akka/stream/Stream.scala
index 2dd2744425..e7a272740f 100644
--- a/akka-stream/src/main/scala/akka/stream/Stream.scala
+++ b/akka-stream/src/main/scala/akka/stream/Stream.scala
@@ -20,7 +20,7 @@ trait Stream[T] {
   def map[U](f: T ⇒ U): Stream[U]
   def filter(p: T ⇒ Boolean): Stream[T]
   def grouped(n: Int): Stream[immutable.Seq[T]]
-  def mapSeq[U](f: T ⇒ immutable.Seq[U]): Stream[U]
+  def mapConcat[U](f: T ⇒ immutable.Seq[U]): Stream[U]
   def transform[S, U](zero: S)(f: (S, T) ⇒ (S, immutable.Seq[U])): Stream[U]
   // FIXME onComplete is not implemented
   // FIXME order of the parameters?
diff --git a/akka-stream/src/main/scala/akka/stream/impl/AbstractProducer.scala b/akka-stream/src/main/scala/akka/stream/impl/AbstractProducer.scala
index 9fca4c0a4f..270e61ddff 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/AbstractProducer.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/AbstractProducer.scala
@@ -266,6 +266,10 @@ private[akka] trait SubscriberManagement[T] extends ResizableMultiReaderRingBuff
   }
 }
 
+/*
+ * FIXME: THIS BELOW NEEDS TO BE REMOVED, IT IS NOT USED BY ActorProcessorImpl
+ */
+
 /**
  * INTERNAL API
  *
diff --git a/akka-stream/src/main/scala/akka/stream/impl/StreamImpl.scala b/akka-stream/src/main/scala/akka/stream/impl/StreamImpl.scala
index ad9a7afa59..71e9656ab2 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/StreamImpl.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/StreamImpl.scala
@@ -40,7 +40,7 @@ private[akka] case class StreamImpl[I, O](producer: Producer[I], ops: List[Ast.A
       else (group, Nil)
     }
 
-  def mapSeq[U](f: O ⇒ immutable.Seq[U]): Stream[U] = transform(())((_, in) ⇒ ((), f(in)))
+  def mapConcat[U](f: O ⇒ immutable.Seq[U]): Stream[U] = transform(())((_, in) ⇒ ((), f(in)))
 
   def transform[S, U](zero: S)(f: (S, O) ⇒ (S, immutable.Seq[U])): Stream[U] = transform(zero, (_: S) ⇒ Nil)(f)