diff --git a/mindboggle/shapes/volume_shapes.py b/mindboggle/shapes/volume_shapes.py
index d9d472d62..71b61fbee 100644
--- a/mindboggle/shapes/volume_shapes.py
+++ b/mindboggle/shapes/volume_shapes.py
@@ -136,7 +136,7 @@ def thickinthehead(segmented_file, labeled_file,
     Compute a simple thickness measure for each labeled cortex region volume.
 
     Since Mindboggle accepts FreeSurfer data as input, we include FreeSurfer
-    cortical thickness estimates with Mindboggle’s shape measures.
+    cortical thickness estimates with Mindboggle's shape measures.
     However, surface mesh reconstruction from MRI data does not always
     produce favorable results. For example, we found that at least a quarter
     of the over one hundred EMBARC brain images we processed through
@@ -411,4 +411,4 @@ def thickinthehead(segmented_file, labeled_file,
 # ============================================================================
 if __name__ == "__main__":
     import doctest
-    doctest.testmod(verbose=True)  # py.test --doctest-modules
\ No newline at end of file
+    doctest.testmod(verbose=True)  # py.test --doctest-modules