diff --git a/src/js/ripple/transaction.js b/src/js/ripple/transaction.js
index cbb0b018..a4d0b524 100644
--- a/src/js/ripple/transaction.js
+++ b/src/js/ripple/transaction.js
@@ -612,7 +612,7 @@ Transaction.prototype.addMemo = function(type, data) {
   }
 
   if (!/(undefined|string)/.test(typeof data)) {
-    throw new Error('MemoData must be string');
+    throw new Error('MemoData must be a string');
   }
 
   function toHex(str) {
diff --git a/test/transaction-test.js b/test/transaction-test.js
index df7aae62..35ba628b 100644
--- a/test/transaction-test.js
+++ b/test/transaction-test.js
@@ -1050,7 +1050,7 @@ describe('Transaction', function() {
 
     assert.throws(function() {
       transaction.addMemo(1);
-    }, 'MemoType must be a string');
+    }, /^Error: MemoType must be a string$/);
   });
 
   it('Add Memo - invalid MemoData', function() {
@@ -1059,7 +1059,7 @@ describe('Transaction', function() {
 
     assert.throws(function() {
       transaction.addMemo('key', 1);
-    }, 'MemoData must be a string');
+    }, /^Error: MemoData must be a string$/);
   });
 
   it('Construct AccountSet transaction', function() {