diff --git a/include/wx/mac/carbon/bitmap.h b/include/wx/mac/carbon/bitmap.h
index 64bc3dad04..a9b14b7713 100644
--- a/include/wx/mac/carbon/bitmap.h
+++ b/include/wx/mac/carbon/bitmap.h
@@ -46,7 +46,7 @@ public:
     // Construct a mask from a mono bitmap (black meaning show pixels, white meaning transparent)
     wxMask(const wxBitmap& bitmap);
     
-    // implementation helper only : construct a mask from a 8 bit memory buffer
+    // implementation helper only : construct a mask from a 32 bit memory buffer
     wxMask(const wxMemoryBuffer& buf, int width , int height , int bytesPerRow ) ;
 
     ~wxMask();