152 DR. WALTER KIDD ON THE [June 17, 



Frontal. — The arrangement of hair here need not be stated at 

 any length ; it is sufficient to point out that a whorl is found at 

 very different levels in varying forms of head, from a position 

 low down almost on the nasal region, in the Domestic Ass, to a 

 point near the level of the external eai's, as in certain Bovidse. 

 A tolerably constant fact connected with it is that from it 

 proceeds a feathering, which passes towaids the ears and termi- 

 nates in a crest. In this instance, as in otheis, the wdioi'l indicates 

 the commencement, and the crest the cessation of a very pei'sistent 

 and strong muscular action common to the life of the animal, 

 effectively leaving an indelible mai^k on the haiiy covering. This 

 frontal whorl lies just over a group of muscles whose fibres pull 

 in veiy diA^ei-gent directions ; and the crest is situated where the 

 effect of the traction of the former muscles becomes neutralized 

 by the opposing temporal muscles. The pai-ticular animal habit, 

 indicated by these arrangements of hair, is most pi'obably associ- 

 ated with the incessant action during numerous houis of the day 

 spent, on the one hand, by the animal in feeding and cropping 

 herbage, and on the othei- in active locomotion. All of these 

 actions tend to employ powei'f ully the maxillaris muscle, oi- levatoi- 

 labii supeiioi'is et alfe nasi, which in the former raises the upper 

 lip, and in the latter dilates the nostiil. These actions of the 

 maxillai-is muscle are best obserA^ed in the browsing habits of 

 Oxen and the locomotive habits of the Hoi'se. Again, the 

 Domestic Hoi'se is useful for study in this matter, for its pre- 

 ponderating activity of locomotion agrees with the fact that this 

 frontal whorl is more marked and persistent than in any other 

 animal. 



In the Horse this frontal whorl lies at the level of the orbits in 

 the majority of cases ; in the Domestic Ass so low down as to be 

 on the nasal region as a rule ; in the Mule it is situated midway 

 between the positions of the Horse and Ass. 



In all Zebi-as examined it has been found that the frontal whorl 

 feathering and crest are singularly ill-developed, and even often 

 absent. This difference in an animal so similar in form to a 

 horse is peculiar, and probably is connected with the fact that 

 though Zebras are capable of very active locomotion, they differ 

 very materially from Horses in the general character of their 

 lives, not being incessantly occupied in locomotion on behalf of 

 man as the domestic horse has been since it was domesticated. 

 Thus in wild Equidse one very important action of the maxillaris 

 muscle is occasional and much less strong than in the horse, and 

 is also less strong than in the ass and mide. 



The Spinal region in the middle line shows in the hair of 

 certain animals, chiefly Ungulates, very vaiying results of their 

 varying habits ; and the simplest instance of these ai'rangements is 

 to be seen in the view from above of the back of an Ox, or prefer- 

 ably a calf (text-fig. 30, p. 153), the young animal showing the points 

 more clearly. In this view the parietal region of the extended head 

 may also be examined. In the frontal region is seen the frontal 



