diff --git a/meshmode/mesh/__init__.py b/meshmode/mesh/__init__.py
index 2cace654250703b073c5895b13191d44f494147e..3ec8222d2450d786060e3218bf306a0da61f23b0 100644
--- a/meshmode/mesh/__init__.py
+++ b/meshmode/mesh/__init__.py
@@ -155,7 +155,7 @@ class SimplexElementGroup(MeshElementGroup):
 
     def face_vertex_indices(self):
         if self.dim == 1:
-            return ((0, 1))
+            return ((0, 1),)
         elif self.dim == 2:
             return (
                 (0, 1),