THE HORSE. 



53 



OS HYOIDES (bone OF THE TONGUe). 



Q. What is the situation of the os 



hyoides 



A. It is located at the root of 



the tongue, at the anterior part of the larynx. 



Q. How is the bone divided ? — A. Into 

 a body and four horns. 



Q. What is the form of the body ? — A. 

 In shape, it resembles a spur, consisting of 

 neck and branches ; the neck is inserted 

 into the root of the tongue, and the branches 

 are in a posterior direction, embracing the 

 superior border of the thyroid cartilage. 



Q. What is the appearance of the horns ? 

 — A. There are two long and two short 

 horns ; the short, or inferior, ascend oblique- 

 ly from their articulations with the body of 

 the bone, and terminate in oblong, smooth 

 extremities. The long or superior horns 

 constitute two long, flattened, thin bones, 

 extending backward in a horizontal direc- 

 tion from the summits of the inferior horns. 



Q. What are the connections of the os 

 hyoides ? — A. It is connected with the 

 temporal bone, larynx, pharynx, tongue, and 

 some of the muscles of the neck. 



OF THE teeth. 



Q. How many teeth do we find in the 

 jaws of the adult horse? — A. Forty. In 

 the mare, however, the canine teeth are 

 generally imperfect or undeveloped. 



Q. How are the teeth divided? — A. 

 Into tlu-ee classes, viz. : incisors, or nippers ; 

 molars, or grinders ; canini, or tusks. 



A. Enumerate each class. — A. There 

 are twelve incisors, twenty-four molars, and 

 four canine. 



Q. Is there anything peculiar about the 

 development of horses' teeth ? — A. Yes ; 

 the teeth with which the animal is furnished 

 during colthood are termed temporary, and 

 are generally shed ere the animal arrives at 

 the age of five ; the temporary teeth are 

 twenty-four in number, twelve incisors and 

 twelve molars ; they differ from what is 

 termed the " permanent set," in being small- 

 er and whiter, and in having necks or con- 

 tractions at the superior part of the fang, 

 and the eminences on their face are quite 



sharp. The converse is the case with regard 

 to the permanent teeth. 



Q. What is the popular theory regarding 

 the periods of cutting the teeth? — A. A 

 foal is said, at birth, to be in the act of cut- 

 ting twelve molars, three on each side of 

 the jaw bone; at this time, there is no ap- 

 pearance of incisors ; and when they do 

 appear, which period vdU. be about the 

 second or third week from birth, sometimes 

 sooner, the front incisors of the upper jaw 

 are the first to show themselves, and be- 

 tween the fourth and fifth week, they are 

 succeeded by the middle incisors ; the side 

 or lateral incisors make their appearance 

 between the sixth and tenth month. The 

 animal is then said to have a full set of 

 temporary teeth. After the animal has at- 

 tained his first year, the fourth molars make 

 their appearance. Between the period of 

 the first and second years, the fifth molars, 

 in each side of the jaw, are apparent. Be- 

 tween the second and third years, the front 

 permanent incisors displace the temporary, 

 and, at the same time, the first temporary 

 molars are shed, and replaced by the perma- 

 nent. Between the thfrd and fourth j^ears, 

 the middle temporary incisors are succeeded 

 by the permanent, and about the same time 

 the second temporary molars are shed. 

 During the inter\'al of the fourth and fifth 

 years, the lateral permanent incisors appear ; 

 the sixth and last, permanent molars are 

 up, and then the tusks also appear. At this 

 period the horse is said to have a full mouth; 

 a complete set of permanent teeth.* 



We have now arrived at an era (or re- 



=* On this side the Atlantic we are not in possession of 

 any reliable information as regards the peiiods of cutting 

 and shedding teeth ; we have to depend entirely on English 

 authoi-ity. Their theory is, that the age of a race-horse shall 

 be reckoned from the month of May in the year of his 

 birth, without any inquiiy whatever as to the season, 

 month, or day of foaling ; so that the produce of January 

 are actually four months older than by reckoning, or as 

 their ages appear on the calendar, and these arc called 

 early foals ; whereas those foaled in ilarch are denomi- 

 nated late. These data are more arbitraiy than truthful ; 

 may suit the convenience of English turfmen, but will not 

 pass current among om* breeders, — who, generally, pay 

 particular attention to the time of foaling, and date the 

 bu'th of the colt accordingly. 



