monotreme

/mon-uh-treem/US // ˈmɒn əˌtrim //UK // (ˈmɒnəʊˌtriːm) //

单纯的,单晶硅,单晶晶,单晶石

Definitions

n.名词 noun

1
- : any animal of the Monotremata, the most primitive order of mammals, characterized by certain birdlike and reptilian features, as hatching young from eggs, and having a single opening for the digestive, urinary, and genital organs, comprising only the duckbill and the echidnas of Australia and New Guinea.

Pseu′dodont, having false teeth, as a monotreme; Pseu′dodox, false.
The oviparous monotreme and the marsupial almost certainly represent lower mammalian ancestral stages.
Moreover, it requires a large amount of material to form a mammalian egg, such as that of the monotreme.
One monotreme egg represents more economy and saving than a thousand eggs of a worm.
It is enough that the living Monotreme and Marsupial so finely illustrate the transition from a reptilian to a mammalian form.