Fig. 25 shows the male genito-urinary tract and the cloaca in the monotreme, Platypus anatinus.
Pseu′dodont, having false teeth, as a monotreme; Pseu′dodox, false.
One monotreme egg represents more economy and saving than a thousand eggs of a worm.
Moreover, it requires a large amount of material to form a mammalian egg, such as that of the monotreme.
That bone is known in a separate state in reptiles and, I think, in monotreme mammals.
Any of various mammals of the order Monotremata. Monotremes are the most primitive type of living mammal. They lay eggs and have a single opening (cloaca) for reproduction and elimination of wastes. The females have no teats but provide milk directly through the skin to their young. The only living monotremes are the duck-billed platypus, found in Australia and New Guinea, and the echidnas, found in New Guinea. Monotremes may have evolved already in the Jurassic Period, but the precise nature of their relationship to marsupials and placental mammals is disputed.