The upcoming discussion will update you about the difference between metatherian and eutherian.
Difference # Metatherian:
1. Marsupium (Brood pouch in the abdomen):
Present in most females [absent in Australian numbat (marsupial ant- eater—Myrmecobius fasciatus), American Chironectes, Marmosa, and Monodelphis]
2. Young:
Extremely immature young’s are born and complete their development in the marsupium.
3. Vagina:
Double vagina (= Didelphia). The vaginae are separate and each has a separate opening into the urinogenital canal.
4. Ureters:
Ureters pass between the genital ducts in both sexes.
5. Corpus callosum:
Corpus callosum is absent or is feebly developed.
6. Dentition:
Monophyodont except the last premolar.
7. Epipubic bone:
Epipubic or marsupial bones are found and remain attached to the pubis.
8. Palate:
The palate is incompletely ossified and is fenestrated.
9. Zygomatic arch:
The jugal bone of the zygomatic arch extends far back to form the glenoid fossa for articulating with the lower jaw.
10. Placenta:
Yolk-sac placenta is developed except Perameles, Phascolarctos and Phascolomys where chorioallantoic Placenta is seen.
Examples:
Macropus, Didelphis, Dasyurus.
Difference # Eutherian:
1. Marsupium (Brood pouch in the abdomen):
Absent.
2. Young:
Mature young’s are born
3. Vagina:
Single vagina
4. Ureters:
Ureters pass outside the ducts.
5. Corpuscallosum:
Well-developed.
6. Dentition:
Diphyodont (except toothed whales, where monophyodont type of dentition is observed)
7. Epipubic bone:
Absent
8. Palate:
Palate is fully ossified.
9. Zygomaticarch:
The jugal bone of the zygomatic arch does not extend far back except in Hyrax and in many rodents.
10. Placenta:
Chorioallantioc placenta is developed
Example:
Mus, Bos, Panthera, axis Elephas.