Why Are There No Upper Incisors in the Buminaiia ? 147 



WHY ARE THERE NO UPPER INCISORS IN THE 

 RUMINANTI A ? 



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 hiM of fare written in indelible charac- 

 ters on his teeih. 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 ruminantia, 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 



