Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct - for the use of schools and colleges (1870) (14596000440)
Zusammenfassung
Identifier: outlinesofcompar00agas (find matches)
Title: Outlines of comparative physiology touching the structure and development of the races of animals, living and extinct : for the use of schools and colleges
Year: 1870 (1870s)
Authors: Agassiz, Louis, 1807-1873 Gould, Augustus A. (Augustus Addison), 1805-1866 Wright, Thomas, 1809-1884
Subjects: Physiology, Comparative Zoology
Publisher: London : Bell & Daldy
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library
Text Appearing Before Image:
Posterior face. BONES Or THE SKULL. 121 The nead is almostin equilibrium on thecondyles (16,16), butthat portion situatedin front of the jointis heavier than thatplaced behind it,hence it overweighsthe latter : this ne-cessitates the presenceof more powerfulmuscles in the pos-terior region of theneck, to maintain thehead erect upon thespinal column; whenthese become relaxed,as in sleep, the headfalls forward upon thechest. (§ 246. The sphe-noid and ethmoidbones, Fig. 91 (1,2),are wedged betweenthe cranial bones atthe base of the skull,and may be said to becommon to the cra-nium and the face. (§ 247. The face isformed by the unionof fourteen differentshaped bones, whichform five large cavi- 4ties for lodging theorgans of vision, smell,and taste. All thebones of the face, thelower jaw excepted,are completely im-moveable, and firmlyunited to each other Fig. 90.
Text Appearing After Image:
122 BONES OF THE SKULL. Fig. 91. and to the bones of the skull; the principal of these are thesuperior maxillaries, Fig. 92 (2), forming nearly the whole of the upper jaw, and whichare connected with thefrontal bone in such amanner as to contributeto the formation of theorbits (4) and the nasalcavities (fig. 93,6); theyform the anterior partof the roof of the mouth,and unite with the malarbones (1), to constitutethe prominence of thecheeks ; behind theyunite with the palatebones. In the interior ofthe nasal fossee are found two spongy bones (figs. 94 and 95),curiously folded, upon which the mucous membrane of the noseFig. 92. Fig. 93.