[116] These bones however have no connection with the marsupium, being nearly equally developed in both male and female. They are simply sesamoid bones forming ossifications in the inner tendon of the external oblique muscle, and are developed as supports for the abdominal wall. Very similar structures have been independently developed in various Amphibians, Reptiles and monodelphian Mammals. See W. Leche, Biol. Fören. III. p. 120.
[117] See H. Gadow, P.Z.S. 1892, p. 361.
[118] See W.H. Flower, "On the Mutual Affinities of the Animals composing the order Edentata," P.Z.S. 1882, p. 358. For the fossil Edentates of N. America see E. Cope, Amer. Natural. 1889; for those of S. America see various papers by F. Ameghino, H. Burmeister and R. Owen. Also T.H. Huxley, "On the Osteology of Glyptodon," Phil. Trans. 1865.
[119] See J.F. Brandt, Symbolae Sirenologicae, St Petersburg, 1846, 1861, 1868.
[120] Epiphyses are fully developed in Halitherium, and traces occur in Manatus.
[121] See P.J. van Beneden and P. Gervais, Ostéographie des Cétacés, 1869-80.
[122] H. Wincza, Morphol. Jahrb. XVI., p. 647.
[123] See M. Pavlow, "Études sur l'histoire paléontologique des Ongulés." Bull. Soc. Moscou, 1887—1890.
[124] In a plantigrade animal the whole of the foot is placed on the ground in walking. A digitigrade animal places only its toes on the ground. An intermediate condition is distinguished by the term subplantigrade.
[125] See p. 345.