diff --git a/monadic-recursion-schemes.cabal b/monadic-recursion-schemes.cabal
--- a/monadic-recursion-schemes.cabal
+++ b/monadic-recursion-schemes.cabal
@@ -4,7 +4,7 @@
 -- http://haskell.org/cabal/users-guide/
 
 name:                monadic-recursion-schemes
-version:             0.1.1.0
+version:             0.1.2.0
 synopsis:            Recursion Schemes for Monadic version.
 description:         Yet another recursion schemes for monadic style, depends on recursion-schemes.
 homepage:            https://github.com/cutsea110/monadic-recursion-schemes.git
diff --git a/src/Data/Functor/Foldable/Monadic.hs b/src/Data/Functor/Foldable/Monadic.hs
--- a/src/Data/Functor/Foldable/Monadic.hs
+++ b/src/Data/Functor/Foldable/Monadic.hs
@@ -1,15 +1,18 @@
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE DeriveFoldable #-}
 {-# LANGUAGE DeriveTraversable #-}
-{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE AllowAmbiguousTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 module Data.Functor.Foldable.Monadic
   ( cataM, anaM
   , paraM, apoM
   , histoM, futuM
   , histoM', futuM'
   , zygoM, cozygoM
-  , hyloM
+  , hyloM, metaM
   ) where
 
 import           Control.Comonad              (Comonad (..))
@@ -51,7 +54,7 @@
 apoM psi = h
   where h = (return . embed) <=< mapM (either return h) <=< psi
 
--- | histomorphism on recursion variant
+-- | histomorphism on anamorphism variant
 histoM :: (Monad m, Traversable (Base t), Recursive t)
        => (Base t (Cofree (Base t) a) -> m a) -- ^ algebra
        -> t -> m a
@@ -66,7 +69,7 @@
 histoM' phi = return . extract <=< cataM f
   where f = return . uncurry (:<) <=< (liftM2 (,) <$> phi <*> return)
 
--- | futumorphism on recursion variant
+-- | futumorphism on catamorphism variant
 futuM :: (Monad m, Traversable (Base t), Corecursive t)
       => (a -> m (Base t (Free (Base t) a))) -- ^ coalgebra
       -> a -> m t
@@ -78,8 +81,8 @@
 
 -- | futumorphism on anamorphism variant
 futuM' :: (Monad m, Traversable (Base t), Corecursive t)
-      => (a -> m (Base t (Free (Base t) a))) -- ^ coalgebra
-      -> a -> m t
+       => (a -> m (Base t (Free (Base t) a))) -- ^ coalgebra
+       -> a -> m t
 futuM' psi = anaM f . Pure
   where f (Pure  a) = psi a
         f (Free fb) = return fb
@@ -100,10 +103,33 @@
 cozygoM f psi = anaM g . Right
   where g = either (return . fmap Left <=< f) psi
 
--- | hylomorphism
+-- | hylomorphism on recursive variant
 hyloM :: (Monad m, Traversable t)
       => (t b -> m b)   -- ^ algebra
       -> (a -> m (t a)) -- ^ coalgebra
       -> a -> m b
 hyloM phi psi = h
   where h = phi <=< mapM h <=< psi
+
+-- FIXME: I couldn't compile with this type signature.
+-- | hylomorphism on combination variant of ana to cata
+-- hyloM' :: (Monad m, Traversable (Base t), Recursive t, Corecursive t)
+--        => (Base t b -> m b)   -- ^ algebra
+--        -> (a -> m (Base t a)) -- ^ coalgebra
+--        -> a -> m b
+hyloM' phi psi = cataM phi <=< anaM psi
+
+-- | metamorphism on recursive variant
+metaM :: (Monad m, Traversable (Base t), Recursive s, Corecursive t, Base s ~ Base t)
+      => (Base t t -> m t)
+      -> (s -> m (Base s s))
+      -> s -> m t
+metaM phi psi = h
+  where h = (return . embed) <=< mapM h . project
+
+-- | metamorphism on combination variant of cata to ana
+metaM' :: (Monad m, Corecursive c, Traversable (Base c), Traversable (Base t), Recursive t)
+       => (Base t a -> m a)   -- ^ algebra
+       -> (a -> m (Base c a)) -- ^ coalgebra
+       -> t -> m c
+metaM' phi psi = anaM psi <=< cataM phi