diff --git a/networks.rkt b/networks.rkt
index 96cec5b..82b053f 100644
--- a/networks.rkt
+++ b/networks.rkt
@@ -542,7 +542,8 @@
   ;; passing type parameters to the parent.
   ;;
   ;; NOTE: The type appearing when you type dynamics% in the REPL does
-  ;; not directly type check.
+  ;; not directly type check, probably because of the structure types
+  ;; which are fully expanded in the REPL.
   (define-type (Dynamics% a)
     (Instance (Class
                (init (network (Network a) #:optional)