Musculi contrahentes in the ontogenesis of the cat limb

This paper demonstrates the structure and development of the layer of mm. contrahentes in Felis catus (Carnivora). Ontogenesis of the muscle layer was studied on 35 histological series of embryonal extremities and by microdissections of palmar musculature in the domestic cat. It was found that three mm. contrahentes were formed passing to the first, second and fifth digits. A compact anlage of the muscle layer (similar to that in embryos of many mammalian species) has been observed only in foetuses of 15-16 mm crown-rump length. Differentiation of the anlagen of the individual muscles takes place in the foetuses of 20-23 mm crown-rump length.