diff --git a/pandas/core/groupby/generic.py b/pandas/core/groupby/generic.py
index 01784513704b4..2787bacb8f418 100644
--- a/pandas/core/groupby/generic.py
+++ b/pandas/core/groupby/generic.py
@@ -63,7 +63,7 @@ def _iterate_slices(self):
             yield val, slicer(val)
 
     def _cython_agg_general(self, how, alt=None, numeric_only=True,
-                            min_count=-1):
+                            min_count=-1, skipna=True):
         new_items, new_blocks = self._cython_agg_blocks(
             how, alt=alt, numeric_only=numeric_only, min_count=min_count)
         return self._wrap_agged_blocks(new_items, new_blocks)
@@ -144,8 +144,20 @@ def _cython_agg_blocks(self, how, alt=None, numeric_only=True,
 
         return new_items, new_blocks
 
-    def aggregate(self, func, *args, **kwargs):
+    def _get_data_to_aggregate(self):
+        obj = self._obj_with_exclusions
+        if self.axis == 0:
+            return obj.swapaxes(0, 1)._data, 1
+        else:
+            return obj._data, self.axis
+
+    def _post_process_cython_aggregate(self, obj):
+        # undoing kludge from below
+        if self.axis == 0:
+            obj = obj.swapaxes(0, 1)
+        return obj
 
+    def aggregate(self, func, *args, **kwargs):
         _level = kwargs.pop('_level', None)
         result, how = self._aggregate(func, _level=_level, *args, **kwargs)
         if how is None: