MUSCLES OF THE PIG — MUSCLES OF HEAD 311 



springs from the outer surface of the tul)erosity of the tibia; the outer, smaller 

 one (M. extensor hallucis longus) , from the upper part of the external border of the 

 tibia and the fibrous band which replaces the shaft of the fibula. The tendon 

 perforates that of the preceding muscle and ends on the metatarsal and second and 

 third tarsal bones. 



B. Posterior Group 



The gastrocnemius and soleus resemble those of the horse. The superficial 

 flexor is more fleshy than in the horse. Its tendon terminates as in the fore limb. 



The deep flexor has in its upper part a close resemblance to that of the horse, 

 but the superficial head (tibialis posterior) is larger and distinct. The tendon ends 

 like that on the fore limb. 



MUSCLES OF THE PIG 

 MUSCXES OF HEAD 



The facial panniculus is pale, thin, and difficult to separate from the skin. 



The orbicularis oris is little develoj^ed. 



The levator nasolabialis is thin and pale, and is undivided. 



The levator labii superioris proprius may well be termed the levator rostri. 

 It has a large ])euniform belly, which arises in the fossa on the lacrimal bone and 

 maxilla. The tendon ends on the anterior part of the os rostri. A muscular slip 

 connects it with the premaxilla. 



The zygomaticus arises on the fascia over the masseter and ends at the angle 

 of the mouth. 



The depressor labii inferioris scj^arates from the Iniccinator only near the 

 angle of the mouth; it ends by a number of tendinous Ijranches in the lower lip. 



The dilatator naris lateralis is well developed. It arises under the levator 

 rostri and ends by a tendinous network around the nostril. 



The dilatator naris transversus is represented only by a few fibers which cross 

 over the os rostri. 



The depressor rostri arises on the facial crest. It has a long strong tendon 

 which passes below the nostril and turns up and inward to meet the tendon of the 

 opposite side and end in the skin of the snout. It depresses the snout and con- 

 tracts the nostril. 



The malaris is absent, and the other palpebral muscles present no special 

 features. 



MUSCLES OF MASTICATION 

 The digastricus has only one IjcUy. It ends on the inner and lower surface 

 of the mandible, in front ^^f the groove for the facial vessels. 

 The other muscles have no important differential features. 

 The same is true of the oral hyoid muscles. 



MUSCLES OF THE NECK 



The panniculus camosus consists of two layers which cross each other ob- 

 liquely. The fi}:)ers of the superficial layer are directed nearly vertically, those of 

 the deep layer toward the face, on which they are continued to form the facial 

 portion. 



The mastoido-humeralis is described on p. 314. 



