diff --git a/Cantera/cxx/include/GRI30.h b/Cantera/cxx/include/GRI30.h
index ca480dca7..1817cf9ca 100644
--- a/Cantera/cxx/include/GRI30.h
+++ b/Cantera/cxx/include/GRI30.h
@@ -1,5 +1,8 @@
-#ifndef CXX_IDEALGASMIX
-#define CXX_IDEALGASMIX
+/*
+ * $Id$
+ */
+#ifndef CXX_GRI30H
+#define CXX_GRI30H
 
 #include <string>