diff --git a/ext/opencv/cvcontour.cpp b/ext/opencv/cvcontour.cpp
index de3842a..b6dfd2b 100644
--- a/ext/opencv/cvcontour.cpp
+++ b/ext/opencv/cvcontour.cpp
@@ -80,8 +80,7 @@ define_ruby_class()
 VALUE
 rb_allocate(VALUE klass)
 {
-  CvContour *ptr;
-  return Data_Make_Struct(klass, CvContour, mark_root_object, unregister_object, ptr);
+  return Data_Wrap_Struct(klass, mark_root_object, unregister_object, NULL);
 }
 
 VALUE
@@ -95,15 +94,15 @@ rb_initialize(int argc, VALUE *argv, VALUE self)
   else
     storage = CHECK_CVMEMSTORAGE(storage);
 
-  CvContour* contour = (CvContour*)DATA_PTR(self);
   try {
-    contour = (CvContour*)cvCreateSeq(CV_SEQ_ELTYPE_POINT, sizeof(CvContour),
-				      sizeof(CvPoint), CVMEMSTORAGE(storage));
+    DATA_PTR(self) = (CvContour*)cvCreateSeq(CV_SEQ_ELTYPE_POINT, sizeof(CvContour),
+					     sizeof(CvPoint), CVMEMSTORAGE(storage));
   }
   catch (cv::Exception& e) {
     raise_cverror(e);
   }
-  register_root_object((CvSeq*)contour, storage);
+  cCvSeq::register_elem_class(CVSEQ(self), cCvPoint::rb_class());
+  register_root_object(CVSEQ(self), storage);
 
   return self;
 }
diff --git a/ext/opencv/cvseq.h b/ext/opencv/cvseq.h
index c486cfc..9e58173 100644
--- a/ext/opencv/cvseq.h
+++ b/ext/opencv/cvseq.h
@@ -22,6 +22,8 @@ VALUE rb_class();
 void define_ruby_class();
 
 VALUE seqblock_class(void *ptr);
+void register_elem_class(CvSeq *seq, VALUE klass);
+void unregister_elem_class(void *ptr);
 
 VALUE rb_allocate(VALUE klass);