diff --git a/library.scm b/library.scm
index fd2b0620..8d6d59e3 100644
--- a/library.scm
+++ b/library.scm
@@ -3947,7 +3947,7 @@ EOF
 ; 4:  (close PORT DIRECTION)
 ; 5:  (flush-output PORT)
 ; 6:  (char-ready? PORT) -> BOOL
-; 7:  (read-bytevector! PORT COUNT BYTEVECTOR START) -> COUNT'
+; 7:  (read-bytevector! BYTEVECTOR PORT START END) -> COUNT'
 ; 8:  (read-line PORT LIMIT) -> STRING | EOF
 ; 9:  (read-buffered PORT) -> STRING