On the other hand, it is noteworthy that this marsupial retains in its lower jaw the so-called mylo-hyoid groove, which is found in the aforesaid Jurassic mammals.
The Hyoid apparatus is, in its detail, subject to many variations in accord with the very diverse uses to which the tongue of birds is III.
(4) A pair of thyrohyals, homologous with the posterior hyoid horns of mammals, i.e.
As the most developed pair in birds they are com monly, although wrongly, called the hyoid horns.
The high cheek-bone and the hawk's bill nose are universally distributed in the two Americas; so also are proportions between parts of the body, and the frequency of certain abnormalities of the skull, the hyoid bone, the humerus and the tibia.
This appendage is merely a fold of the skin, ornamental and sexual; it has no cavity in its interior, and has no communication with the mouth or with the respiratory organs; it is supported by the posterior horns of the hyoid bone, and can be erected and spread at the will of the animal.
Both as regards structure and habits, the leopard may be reckoned as one of the more typical representatives of the genus Felis, belonging to that section in which the hyoid bone is loosely connected with the skull, owing to imperfect ossification of its anterior arch, and the pupil of the eye when contracted under the influence of light is circular, not linear as in the smaller cats.
The hyoid arch is unlike that of any known mammal.
In the floor of the mouth, between the two branches of the lower jaw, and supported behind by the hyoid apparatus, lies the tongue, an organ the free surface of which, especially in its posterior part, is devoted to the sense of taste, but which by reason of its great mobility (being composed almost entirely of muscular fibres) performs important mechanical functions connected with masticating and procuring food.
M.h.l, Mandibulo-hyoid ligament.
- Hyoid and branchial apparatus of Necturus maculosus.
- Ventral view of the hyoid of Rana esculenta.