Page:Popular Science Monthly Volume 40.djvu/674

 hand, the front teeth, of the Notoryctes are small, hardly more than pegs, and leave a considerable gap on the median line, a disposition like that observed in some of the edentates. It might be well to compare this dentition with that of the Myrmecobia, which is also Australian, and with that of some of the types of Eocene fossil mammals which have recently been discovered in



South America. The angular apophysis of the lower jaw is markedly bent within, a tolerably constant characteristic of the opossums. The marsupial bones, on the other hand, are but little developed. They are represented only by two small osseous nodules diverging forward and united in the tendon of the oblique external muscle of the abdomen at its insertion on the symphysis of the pubis. They are hardly visible with the lens, and might easily pass undetected in a hasty or superficial dissection. Nothing is yet known of the method of reproduction of the Notoryctes.

As a whole, we are struck by the resemblances exhibited between the Notoryctes and the African Chrysochlores; the forms of the skull, of the molar teeth, and of the fore limb are such as to lead us to suppose something more than a simple secondary adaptation depending on an identical mode of life. The unlikeness, on the contrary, between the incisors and the canine teeth of the two types is deserving of closer study. It is of interest to recollect that these two genera are not the only ones which establish by their outer forms a bond of relationship between the South African and the Australian fauna. The Pedetes (Helamy), or great jerboa of the Cape, exhibits absolutely the forms of the Australian kangaroos, although it is a placentary rodent. There are also well-known relations between the South African and the Australian flora.—Translated for The Popular Science Monthly from La Nature.