I find a lot of centipedes and millipedes when digging in the garden, usually the same orange or smooth, dark and shiny versions respectively. So I was intrigued when I found this unusual millipede, which has a spiky but flattened back compared to the usual near cylindrical millipede with which I'm familiar. It is indeed called a Flat-backed millipede and is apparently fairly common. Still it was the first I'd seen. More info and a top-down shot after the break…

Like all millipedes, it's a vegetarian and eats decaying plant matter so is usually found amongst leaf litter, in compost heaps and under logs. Centipedes on the other hand are carnivorous and equipped with fairly vicious fangs up front. if you don't have time to wait and see what a specimen eats in order to identify it, the key difference is pairs of legs. Centipedes have one pair per body segment. Millipedes like that above have 2 pairs per body segment (although by my count that doesn't seem to be true for the whole length of this example).