Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume IV (1876-1877)
Hoy, P. R.
Why are there no upper incisors in the Ruminantia?, pp. 147-150 PDF (1.0 MB)
Why Are There No Upper Incisors in the Rumninatia? 147 WHY ARE THERE NO UPPER INCISORS IN THE RUMINANTIA? BY P. R. HOY, M. D., PREST. ACADEMY. In studying the anatomy and physiology of animals, we become intensely interested in the various modifications of parts, so as to exactly fit them, to perform the office assigned them. In other words, the structures are so altered as to correspond to the mode of life which the animal pursues. Perhaps no part of vertebrates is as significant as the apparatus of the mouth, for obvious reasons, as it performs an important part in nutrition, the function which strikes at the very founda- tion of life. Every vertebrate has his hill of ftre written in indelible charac- ters on his teeth. They not only indicate the food on which the animal subsists, but with few exceptions,- the mode of procuring that food, as well. All those animals having no incisors in the upper jaw, and pro- vided with eight placed obliquely outward in the lower jaw, have evenly divided hoofs, complicated -stomachs, and chew the cud. I am satisfied that there is a deep meaning conveyed in the absence of upper incisors in ruaminantia, if the fact is correctly interpreted. In the first place, all true ruminants have a prehensile tongue. We will take one of the most familiar examples, the cow, and what is true of this domestic animal, will apply equally well, not only to the entire boss family, but with slight modification, to the entire ruminantia. The tongue is large and muscular, weighing from three to five pounds, the upper surface, dorsum, is covered with a dense, almost horny skin, especially at the point; the mucous coat, covering the tongue and lingual glands, pours out an abundance of mucus and saliva to keep the organ moist and plia- ble. it is capable of being thrust out beyond the lips to the dis- tance of from six to eight inches. In protruding the tongue it is pressed firmly against the hardened gum of the upper jaw, then it
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