diff --git a/dlib/general_hash/murmur_hash3.h b/dlib/general_hash/murmur_hash3.h
index b8e37260e..e89edebd8 100644
--- a/dlib/general_hash/murmur_hash3.h
+++ b/dlib/general_hash/murmur_hash3.h
@@ -320,7 +320,7 @@ namespace dlib
     inline std::pair<uint64,uint64> murmur_hash3_128bit ( 
         const void* key, 
         const int len,
-        const uint32 seed = 0
+        const uint64 seed = 0
     )
     {
         const uint8 * data = (const uint8*)key;
diff --git a/dlib/general_hash/murmur_hash3_abstract.h b/dlib/general_hash/murmur_hash3_abstract.h
index ef7bc0b41..8aed2db88 100644
--- a/dlib/general_hash/murmur_hash3_abstract.h
+++ b/dlib/general_hash/murmur_hash3_abstract.h
@@ -65,7 +65,7 @@ namespace dlib
     std::pair<uint64,uint64> murmur_hash3_128bit ( 
         const void* key, 
         const int len,
-        const uint32 seed = 0
+        const uint64 seed = 0
     );
     /*!
         requires