diff --git a/Source/NSConnection.m b/Source/NSConnection.m
index c2f35341f..0ea48dea4 100644
--- a/Source/NSConnection.m
+++ b/Source/NSConnection.m
@@ -903,7 +903,8 @@ static int messages_received_count;
 		       outPort: (NSPort*)op
 	    ancestorConnection: (NSConnection*)ancestor
 {
-  NSConnection *newConn;
+  NSNotificationCenter	*nCenter;
+  NSConnection		*newConn;
 
   NSParameterAssert (ip);
 
@@ -1034,15 +1035,16 @@ static int messages_received_count;
 
   /* Register ourselves for invalidation notification when the
      ports become invalid. */
-  [NSNotificationCenter addObserver: newConn
-			   selector: @selector(portIsInvalid:)
-			       name: NSPortDidBecomeInvalidNotification
-			     object: ip];
+  nCenter = [NSNotificationCenter defaultCenter];
+  [nCenter addObserver: newConn
+	      selector: @selector(portIsInvalid:)
+		  name: NSPortDidBecomeInvalidNotification
+		object: ip];
   if (op)
-    [NSNotificationCenter addObserver: newConn
-			     selector: @selector(portIsInvalid:)
-				 name: NSPortDidBecomeInvalidNotification
-			       object: op];
+    [nCenter addObserver: newConn
+		selector: @selector(portIsInvalid:)
+		    name: NSPortDidBecomeInvalidNotification
+		  object: op];
   /* if OP is nil, making this notification request would have
      registered us to receive all NSPortDidBecomeInvalidNotification
      requests, independent of which port posted them.  This isn't
diff --git a/Source/NSPortNameServer.m b/Source/NSPortNameServer.m
index 6ecbdd2b9..92c8366a5 100644
--- a/Source/NSPortNameServer.m
+++ b/Source/NSPortNameServer.m
@@ -787,6 +787,7 @@ static NSPortNameServer	*defaultServer = nil;
 
 - (void) _open: (NSString*)host
 {
+  NSNotificationCenter *nc;
   NSRunLoop	*loop;
   NSString	*hostname = host;
   BOOL		isLocal = NO;
@@ -870,18 +871,19 @@ static NSPortNameServer	*defaultServer = nil;
 
   expecting = 1;
   [handle retain];
-  [NSNotificationCenter addObserver: self
-			   selector: @selector(_didConnect:)
-			       name: GSFileHandleConnectCompletionNotification
-			     object: handle];
-  [NSNotificationCenter addObserver: self
-			   selector: @selector(_didRead:)
-			       name: NSFileHandleReadCompletionNotification
-			     object: handle];
-  [NSNotificationCenter addObserver: self
-			   selector: @selector(_didWrite:)
-			       name: GSFileHandleWriteCompletionNotification
-			     object: handle];
+  nc = [NSNotificationCenter defaultCenter];
+  [nc addObserver: self
+	 selector: @selector(_didConnect:)
+	     name: GSFileHandleConnectCompletionNotification
+	   object: handle];
+  [nc addObserver: self
+	 selector: @selector(_didRead:)
+	     name: NSFileHandleReadCompletionNotification
+	   object: handle];
+  [nc addObserver: self
+	 selector: @selector(_didWrite:)
+	     name: GSFileHandleWriteCompletionNotification
+	   object: handle];
   loop = [NSRunLoop currentRunLoop];
   [loop runMode: mode
      beforeDate: [NSDate dateWithTimeIntervalSinceNow: connectTimeout]];
diff --git a/Source/NSSerializer.m b/Source/NSSerializer.m
index 4eef6a157..a6da3775e 100644
--- a/Source/NSSerializer.m
+++ b/Source/NSSerializer.m
@@ -698,7 +698,7 @@ deserializeFromInfo(_NSDeserializerInfo* info)
 	}
       else
 	{
-	  [NSNotificationCenter
+	  [[NSNotificationCenter defaultCenter]
 	    addObserver: self
 	       selector: @selector(_becomeThreaded:)
 		   name: NSWillBecomeMultiThreadedNotification