diff --git a/lib/messages.js b/lib/messages.js
index 89cc4b0..8ff3a94 100644
--- a/lib/messages.js
+++ b/lib/messages.js
@@ -147,7 +147,7 @@ Message.prototype.getPayload = function() {
  * @returns{Buffer} the serialized message
  */
 Message.prototype.serialize = function(network) {
-  $.checkArgument(network);
+  $.checkArgument(network, 'Must specify network for serialization');
   var commandBuf = new Buffer(this.command, 'ascii');
   $.checkState(commandBuf.length <= 12, 'Command name too long');
   var magic = network.networkMagic;
diff --git a/test/data/messages.json b/test/data/messages.json
index 8e89c5f..ea75e8d 100644
--- a/test/data/messages.json
+++ b/test/data/messages.json
@@ -11,6 +11,10 @@
     "message": "",
     "payload": ""
   },
+  "NOTFOUND": {
+    "message": "f9beb4d96e6f74666f756e6400000000250000001d33d53201010000003a4af715be220eae7b2657582869daddf79ac4afb4a0e1cafa5b57e1afb8dfe2",
+    "payload": "01010000003a4af715be220eae7b2657582869daddf79ac4afb4a0e1cafa5b57e1afb8dfe2"
+  },
   "GETBLOCKS": {
     "message": "",
     "payload": ""
diff --git a/test/messages.js b/test/messages.js
index bf1be20..d72e6a6 100644
--- a/test/messages.js
+++ b/test/messages.js
@@ -27,7 +27,8 @@ describe('Messages', function() {
     GetData: 'getdata',
     GetAddresses: 'getaddr',
     Headers: 'headers',
-    Transaction: 'tx'
+    Transaction: 'tx',
+    NotFound: 'notfound'
   };
   // TODO: add data for these 
   var noPayload = ['Alert', 'Reject', 'GetBlocks', 'GetHeaders', 'GetData', 'Headers'];