An introduction to the osteology of the Mammalia / by William Henry Flower.

  • Flower, William Henry, 1831-1899.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to the osteology of the Mammalia / by William Henry Flower. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

    19/408 (page 3)
    can only be deduced from the two existing families, as hitherto no extinct animals which can be referred to other divisions of this remarkable and well-characterised group have been discovered. These two isolated forms, in man)' respects dissimilar, yet having numerous common characters, which unite them together and distinguish them from the rest of the Mammalia, are the OrjiitliorJiyiichidcc and the Echid)tidce,'bo\.h. restricted in their geographical range to the Australian region of the globe. Taken altogether they represent the lowest known type of evolution of the Mam- malian class, and most of the characters in which they differ from the other two sub-classes, tend to connect them with the inferior vertebrates, the Sanropsida and AiiipJiibia ; for though the name Ornilhodclphia owes its origin to the resemblance of the structure of the female reproductive organs to those of birds, there is nothing especially bird-like about them. Their principal distinctive characters are these: The brain has a very large anterior commissure, and a very small corpus callosum, agreeing exactly in this respect with the next group. The cerebral hemispheres, in Ecliidna at least, are well developed and convoluted on the surface. The auditory ossicles present a low grade of development, the malleus being very large, the incus small, and the stapes columelliform. They have no true teeth, though the jaws of OrnithorliyncJius are provided with horny productions, which functionally supply their place. The coracoid bone is complete and articulates with the sternum, and there is a large interclavicle or episternum in front of the sternum and connecting it with the clavicles. There are also epipubic bones. The oviducts (not difterentiated into uterine and Fallopian portions) are completely distinct, and open as in other oviparous vertebrates separately into a cloacal B 2