Assertion: echidna | /r/HasAspect | joined hemipenis
Facets:
Source sentences:
text: Marsupials (another primitive group of mammals) are now in this matter something between monotremes and placental (evolved) mammals: they do not use half of the penis for mating, but still have a double headed penis, while the echidnas have a reptilian joined hemipenis, with each part of the penis in a marsupial-like fashion.