Besides the platypus, Australia's other egg-laying mammal is this one that looks like a porcupine
The four extant 
species, together with the platypus, are the only surviving ... Like the platypus, 
they are equipped with electrosensors, but while the platypus has 40,000... [DOC] [TLE] Egg-laying Mammals :: Saint Louis Zoo [PAR] This animal may have sharp spines, but it isn't a porcupine!