Not a particularly unusual name, but I'm a sucker for alliteration. As far as I can tell, "Mehallalnell" is the clerk's rendering of Mahalaleel, who is mentioned in Genesis 5:12-17. The Biblical Mahalaleel was the great-grandfather of Methuselah and lived to be 895 years old.
Despite his name, Munnings did not enjoy remarkable longevity. He drowned on February 27, 1659/1660.