File:The American Museum journal (c1900-(1918)) (17540423383).jpg

Title: The American Museum journal
Identifier: americanmuseumjo17amer (find matches)
Year: c1900-(1918) (c190s)
Authors: American Museum of Natural History
Subjects: Natural history
Publisher: New York : American Museum of Natural History
Contributing Library: American Museum of Natural History Library
Digitizing Sponsor: Biodiversity Heritage Library

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383 THE AMERICAN MUSEUM JOURNAL bone. It has a special interest, besides, since it possessed another very impor- tant striicture in higlier vertebrates— namely, an eardrum, which was doubt- less stretched upon the bony rim behind the eye-sockets. The Tejn lizard represents a still higher grade of organization, the next step toward the mammals in one direc- tion and toward the birds in another. It is an active, carnivorous animal, and its face is well protected by a mask of scaly skin. The bony mask is also still there, nnder the skin; but here is a ))()int most important to remember, that if you took off the scaly skin of the face in this reptile, you would not find any facial muscles Ijcneatli tlu> skin, such as are present in our own face. It is only on the under side of the jaws and lliroat that vou would find a hiver
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Tlie faci.al musdes are supplied by branches of the seventh or facial nerve, which issues from the skull behind and below the ear. It is be- lieved that the throat muscle in remote ancestors of mammals spreads upward between the bone and the skin, carrying the seventh nerve with it, and that as the muscle branched, the nerve also branched again and again, producing the highly mobile sensitive face of man. From Cun- ningham's Anatomy of muscles beneath the skin. In the ab- sence of true facial muscles all reptiles are inferior in rank to the mammals, where facial muscles first appear. Birds have the immol)ile nonmuscular face of rei)tiles, further masked l)y a horny ))eak or bill; l)ut the mammals have soft mus- cular lips and a muscular layer about the nose, eyes, forehead, and cars. One of the greatest gaps in the whole record of the evolution of the face consists in this, that in spite of the relative abundance of living relies that preserve successive stages in the evolution of the skull itself, there is no animal known which has an intermedi- ate type of face between the immobile iKniinuscuhir face of reptiles and the mobile muscular face of mammals. In spite of this, comparative anatomy fur- nishes fairly clear evidence as to the exact process by which the one did evolve into the other. The facial muscles of a typical mam- mal, a lemur (Pro pith ecus), for in- stance, correspond with the facial muscles of man. They include the pla- tysma covering the throat, the orbicu- lar muscle around the eye, the muscles of the nose, the muscles that lift the \\\^. the muscles that draw back the cor- ners of the mouth, and the buccinator, which is of great use not only in blow- ing a trumpet, as its name suggests, but also in protruding the lips and in jmshing the food aljout inside the mouth. All these various muscles of the face in man are innervated by branches of the seventh or facial nerve. The facial nerve comes out from behind the ear, and turns forward, one branch going to the platysma muscle on the surface of the throat and the other in numer- ous branches and sub-branches, like a vine and its divisions, passing forward to supply the muscles of the face. This

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