534 



ZOOLOGY 



SECT. 



and structure from the molars. In the Horse (Fig. 1124) the 

 formula is 



i 3 c 1 - m 3 = 44 



but the first premolar is a small tooth which soon becomes lost, 

 and may belong to the milk dentition. A fold of the enamel 

 dips downwards (i.e. towards the root) from the extremity of the 

 incisor teeth like the partly inverted finger of a glove ; the 

 canines are small in the female, and may not appear on the sur- 

 face. There is a wide interval in both jaws between the canines 



Ncv 



ML* 



FIG. 1124. Side view of skull of Horse with the bone removed so as to expose the whole of the 

 teeth, c. canine ; i. / 2 - % incisors ; ml. m 2 . m3. molars ; p. m l . situation of the vestigial 

 first pre-molar, which has been lost in the lower, but is present in the upper jaw ; prriZ.pmP.pm 4 . 

 remaining pre-rnolars ; fr. frontal ; ju. jugal ; Icr. lacrymal ; max. maxilla ; na. nasal ; 

 pa. parietal ; par.oc. par-occipital process ; p.maz. pre-maxilla ; oc. cond. occipital condyle ; 

 sq. squamosal. (After Flower and Lydekker.) 



and pre-molars. The pre-molar and molar teeth present a com- 

 plicated pattern due to folds of the enamel, which differ in their 

 arrangement in the upper and lower jaws ; their roots become 

 completed only at a late period. 



In the Hyracoidea the dental formula is 



.104 3 



* 2' C ' 6'*' 4' m ' 3 = 34 



The upper incisors are not unlike the larger pair of the Rabbit in 

 shape, though prismatic and pointed, instead of compressed and 

 chisel-like, and grow from persistent pulps. The outer incisors 

 are elongated, inclined forwards, and trilobed at the extremities. 



