diff --git a/Source/OrderedCollection.m b/Source/OrderedCollection.m
index f61b274fb..05dff556e 100644
--- a/Source/OrderedCollection.m
+++ b/Source/OrderedCollection.m
@@ -167,13 +167,13 @@
 
 // REPLACING;
 
-- replaceRange: (IndexRange)aRange 
+- (void) replaceRange: (IndexRange)aRange 
    withCollection: (id <ConstantCollecting>)aCollection
 {
   [self notImplemented: _cmd];
 }
 
-- replaceRange: (IndexRange)aRange 
+- (void) replaceRange: (IndexRange)aRange 
    usingCollection: (id <ConstantCollecting>)aCollection
 {
   [self notImplemented: _cmd];