[Position of tylopoda in the system of placental mammals]

Anatomical features of the Tylopoda are determined to a great extent by the convergence with the Ruminantia. The dental system adapted to the double mastification of plant food. The convergent character of the structure of limbs follows from the reduction of carpal and tarsal bones in the Tylopoda and their presence in the Ruminantia. The Ruminantia have no mandibular angular processes which are present in the Tylopoda. In the Tylopoda, the foramina in the transversal processes of cervical vertebrae from a canal by which the vertebral artery opens in the brain. In the Ruminanta there is no such a canal. The embryonic development of camels is characterized by the promitive features of provisory organs. The mating of camels occurs in winter, a feature probably showing that they have preserved the reproduction cycle of the Southern Hemisphere animals.