diff --git a/s48/sequences/composeqs.scm b/s48/sequences/composeqs.scm
index 1e6803d..43a435a 100644
--- a/s48/sequences/composeqs.scm
+++ b/s48/sequences/composeqs.scm
@@ -20,7 +20,7 @@
          (apply vector-fill! s x opts))
         ((string? s)
          (apply string-fill! s x opts))
-        ((pair? s)
+        ((and (pair? s) (null? opts))
          (apply list-fill! s x opts))
         (else
          (apply contiguous-sequence-fill! s x opts))))
diff --git a/s48/sequences/specseqs.scm b/s48/sequences/specseqs.scm
index 044fe3e..1bdb4dd 100644
--- a/s48/sequences/specseqs.scm
+++ b/s48/sequences/specseqs.scm
@@ -11,8 +11,6 @@
 (define (sublist xs start end)
   (take (drop xs start) (- end start)))
 
-;; unspecified return value 
+;; unspecified return value -- no [start end] for now
 (define (list-fill! xs x)
   (pair-for-each (lambda (p) (set-car! p x)) xs))
-
-