diff --git a/model/cs/content-store-nocache.h b/model/cs/content-store-nocache.h
index 98c1850..ca3afe2 100644
--- a/model/cs/content-store-nocache.h
+++ b/model/cs/content-store-nocache.h
@@ -54,11 +54,11 @@
   virtual
   ~Nocache ();
 
-  virtual Ptr<ContentObject>
+  virtual Ptr<Data>
   Lookup (Ptr<const Interest> interest);
 
   virtual bool
-  Add (Ptr<const ContentObject> data);
+  Add (Ptr<const Data> data);
 
   virtual void
   Print (std::ostream &os) const;