1901,] THE MUSCLES OF THE UNGULATA. 661 



II thin sheet of muscle which we found in the Pig M\d Mouflon, 

 and which is figured by Cuvier and Laurillard in the Wild Boar 

 (I.). We are unable to homologize it with any of the facial 

 muscles of human anatomy, but we have little doubt that it is 

 present in more than the two animals in which we have recorded 

 it, and that its thinness and superficial situation have caused it to 

 escape our notice as \^ell as that of other writers. The fibres 

 cover the whole of the side of the snout and run downward and 

 slightly forward to the upper lip. 



Levator labii superioris. — The nomenclature of the lip and nose- 

 muscles of Ungulates is extremely difficult, owing to the fact that 

 the veterinary writers have names of their own, while human 

 anatomists have tried to trace homologies with the muscles of 

 Man's face ; the matter is still further complicated when one 

 realizes that there is almost as much difference between the nose- 

 and lip-muscles of the Horse and the Pig as there is between 

 either of these animals and Man. lu the Horse and Ass the 

 mnscle.' which is usually called levator labii superioris, rises from 

 just in front and below the orbit, and ruus down to the upper lip, 

 its tendon passing with that of the other side between the two 

 nostrils. Physiologically the muscle Avell deserves its name, but 

 it is clearly not the same muscle as the levator labii superioris of 

 Man. 



In the Ox (82) the same muscle is seen, but its origin is much 

 lower down on the maxilla. In other members of the Bovidse, 

 such as the Mouflon Sheep (45) and the Duiker-bok (49) (see 

 text-figs. 86 and 87), this muscle ends in the nose just above the 

 nostril instead of being continued on to the upper lip, and now 

 the name of levator labii superioris becomes objectionable because 

 it is misleading. We should like to suggest that this and the 

 other muscles which run from the maxilla to the nose should be 

 called naso-maxillary muscles, and be identified as siiperior, middle, 

 and inferior, but experience in this direction has shown us the 

 risk of adding to the existing confusion by giving fresh names 

 (see text-fig. 86). 



Levator labii superioris alceqiie nasi. — This muscle is well named 

 in the Horse, and rises from above and in front of the orbit ; 

 below it divides for the side of the nostril and angle of the mouth, 



In the Tapir (55) the muscle is extremely well developed, and 

 in the Ox (32) it is also well-marked. In the Deer and Antelopes 

 it is suppressed, owing to the great development of the suborbital 

 glands ; and in the Sheep (39) and Mouflon (45), where rudiments 

 of this gland persist, the muscle is also absent. In the Suidse, too 

 (5, 7, 10, 11, 13, 14), the muscle is absent, unless its I'udimeuts are 

 present as the superficialis faciei already described. 



Dilator naris (^retractor naris). — There are usually two fleshy 

 bellies rising close together from the canine fossa of the maxilla 

 below the infraorbital foramen, and ending by a number of fine 

 tendons in the skin of the side of the nostril and of the upper lip 

 (see text-fig. 87). As we have already pointed out, in the Bovidse, 



