diff --git a/pelican/contents.py b/pelican/contents.py
index 8a9be817..873e89cd 100644
--- a/pelican/contents.py
+++ b/pelican/contents.py
@@ -112,7 +112,7 @@ class Page(object):
         if 'summary' in metadata:
             self._summary = metadata['summary']
 
-        signals.content_object_init.send(self.__class__, instance=self)
+        signals.content_object_init.send(self)
 
     def check_properties(self):
         """test that each mandatory property is set."""
diff --git a/pelican/plugins/summary.py b/pelican/plugins/summary.py
index cd433b7c..8b1b3ae3 100644
--- a/pelican/plugins/summary.py
+++ b/pelican/plugins/summary.py
@@ -14,7 +14,7 @@ def initialized(pelican):
         pelican.settings.setdefault('SUMMARY_END_MARKER',
                                     '<!-- PELICAN_END_SUMMARY -->')
 
-def content_object_init(PageClass, instance):
+def content_object_init(instance):
     # if summary is already specified, use it
     if 'summary' in instance.metadata:
         return