diff --git a/grudge/symbolic/operators.py b/grudge/symbolic/operators.py
index a1d0f210ad3a94157af431e3610c2e3bdc577d09..c1a006e84be74c8d05945f8522ec4cfd82284974 100644
--- a/grudge/symbolic/operators.py
+++ b/grudge/symbolic/operators.py
@@ -383,16 +383,14 @@ class OppositeRankFaceSwap(Operator):
     def __init__(self, dd_in=None, dd_out=None):
         sym = _sym()
 
-        # from meshmode.mesh import BTAG_PARTITION
         if dd_in is None:
-            # FIXME: What is FRESTR_INTERIOR_FACES?
+            # FIXME: Is this correct?
             dd_in = sym.DOFDesc(sym.FRESTR_INTERIOR_FACES)
-            # dd_in = sym.DOFDesc(BTAG_PARTITION)
         if dd_out is None:
             dd_out = dd_in
 
-        # if dd_in.domain_tag is not BTAG_PARTITION:
-        #     raise ValueError("dd_in must be a rank boundary faces domain")
+        if dd_in.domain_tag is not sym.FRESTR_INTERIOR_FACES:
+            raise ValueError("dd_in must be an interior faces domain")
         if dd_out != dd_in:
             raise ValueError("dd_out and dd_in must be identical")
 
diff --git a/grudge/symbolic/primitives.py b/grudge/symbolic/primitives.py
index 44eb7893dcb0e657b3dbae4c8dbaeeeecb1d7430..173a1a2d9da96dd19dac17674d46590b92c1f795 100644
--- a/grudge/symbolic/primitives.py
+++ b/grudge/symbolic/primitives.py
@@ -183,9 +183,6 @@ class DOFDesc(object):
             pass
         elif domain_tag in [BTAG_ALL, BTAG_REALLY_ALL, BTAG_NONE]:
             pass
-        # FIXME: I think I need to pass BTAG_PARTITION from OppositeRankFaceSwap
-        # elif domain_tag is BTAG_PARTITION:
-        #     pass
         elif isinstance(domain_tag, DTAG_BOUNDARY):
             pass
         else: