diff --git a/gtsam_unstable/CMakeLists.txt b/gtsam_unstable/CMakeLists.txt
index d90cbdecf..54e95a599 100644
--- a/gtsam_unstable/CMakeLists.txt
+++ b/gtsam_unstable/CMakeLists.txt
@@ -71,7 +71,8 @@ if (GTSAM_BUILD_WRAP)
     include(GtsamMatlabWrap)
     
     # Wrap codegen
-    #usage: wrap mexExtension interfacePath moduleName toolboxPath
+    #usage: wrap mexExecutable mexExtension interfacePath moduleName toolboxPath [mexFlags]
+    #  mexExecutable : command to execute mex if on path, use 'mex'
     #  mexExtension  : OS/CPU-dependent extension for MEX binaries
     #  interfacePath : *absolute* path to directory of module interface file
     #  moduleName    : the name of the module, interface file must be called moduleName.h
diff --git a/wrap/CMakeLists.txt b/wrap/CMakeLists.txt
index f0999a9eb..45fb61ec0 100644
--- a/wrap/CMakeLists.txt
+++ b/wrap/CMakeLists.txt
@@ -23,7 +23,8 @@ if (GTSAM_BUILD_TESTS)
 endif(GTSAM_BUILD_TESTS)
 
 # Wrap codegen
-#usage: wrap mexExtension interfacePath moduleName toolboxPath
+#usage: wrap mexExecutable mexExtension interfacePath moduleName toolboxPath [mexFlags]
+#  mexExecutable : command to execute mex if on path, use 'mex'
 #  mexExtension  : OS/CPU-dependent extension for MEX binaries
 #  interfacePath : *absolute* path to directory of module interface file
 #  moduleName    : the name of the module, interface file must be called moduleName.h
diff --git a/wrap/wrap.cpp b/wrap/wrap.cpp
index 453eaa73a..eabba647e 100644
--- a/wrap/wrap.cpp
+++ b/wrap/wrap.cpp
@@ -24,6 +24,7 @@ using namespace std;
 
 /**
  * Top-level function to wrap a module
+ * @param mexCommand is a sufficiently qualified command to execute mex within a makefile
  * @param mexExt is the extension for mex binaries for this os/cpu
  * @param interfacePath path to where interface file lives, e.g., borg/gtsam
  * @param moduleName name of the module to be generated e.g. gtsam
@@ -50,7 +51,7 @@ void generate_matlab_toolbox(
 /** Displays usage information */
 void usage() {
   cerr << "wrap parses an interface file and produces a MATLAB toolbox" << endl;
-  cerr << "usage: wrap mexExtension interfacePath moduleName toolboxPath [mexFlags]" << endl;
+  cerr << "usage: wrap mexExecutable mexExtension interfacePath moduleName toolboxPath [mexFlags]" << endl;
   cerr << "  mexExecutable : command to execute mex if on path, use 'mex'" << endl;
   cerr << "  mexExtension  : OS/CPU-dependent extension for MEX binaries" << endl;
   cerr << "  interfacePath : *absolute* path to directory of module interface file" << endl;