With the Monotremata (q.v.) this group has no.
ECHIDNA, or Porcupine Ant-Eater (Echidna aculeata), one of the few species of Monotremata, the lowest subclass of Mammalia, forming the family Echidnidae.
Thomas, Catalogue of Monotremata and Marsupialia in the British Museum (1888); "On Caenolestes, a Survivor of the Epanorthidae," Proc. Zool.
There are two orders, the Marsupialia and the Monotremata, which do not possess this organ; both these are found in Australia, to which region indeed they are not absolutely confined.
We pass on to the other curious order of non-placental mammals, that of the Monotremata, so called from the structure of their organs of evacuation with a single orifice, as in birds.