diff --git a/csi.scm b/csi.scm
index bcb1022..eb52326 100644
--- a/csi.scm
+++ b/csi.scm
@@ -457,6 +457,12 @@ EOF
 		      (lag (cdr lag)))
 		  (or (eq? x lag) (lp x lag))))))))
 
+(define (improper-pairs? x)
+  (let lp ((x x))
+    (if (not (pair? x)) #f
+       (or (eq? x (car x))
+           (lp (cdr x))))))
+
 (define-constant max-describe-lines 40)
 
 (define describer-table (make-vector 37 '()))
@@ -533,15 +539,17 @@ EOF
 		    (lambda ()
 		      (write (cadr plist) out) ) )
 		   (newline out) ) ) ) ]
-	    [(circular-list? x)
-	     (fprintf out "circular list: ")
+	    [(or (circular-list? x) (improper-pairs? x))
+	     (fprintf out "circular structure: ")
 	     (let loop-print ((x x)
-			      (parsed '()))
-	       (if (not (memq (car x) parsed))
-		   (begin
+                              (cdr-refs (list x)))
+               (cond ((or (atom? x)
+                          (null? x)) (printf "eol~%"))
+                     ((memq (car x) cdr-refs)
+                      (fprintf out "(circle)~%" ))
+                  ((not (memq (car x) cdr-refs))
 		     (fprintf out "~S -> " (car x))
-		     (loop-print (cdr x) (cons (car x) parsed)))
-		   (fprintf out " ~S (circle)~%" (car (memq (car x) parsed)))))]
+                   (loop-print (cdr x) (cons (car x)  cdr-refs) ))))]
 	    [(list? x) (descseq "list" length list-ref 0)]
 	    [(pair? x) (fprintf out "pair with car ~S and cdr ~S~%" (car x) (cdr x))]
 	    [(procedure? x)