echidna: a burrowing monotreme mammal covered with spines and having a long snout and claws for hunting ants and termites; native to Australia
monotreme: the most primitive mammals comprising the only extant members of the subclass Prototheria
genus clostridium: anaerobic or micro-aerophilic rod-shaped or spindle-shaped saprophytes; nearly cosmopolitan in soil, animal intestines, and dung