292 THE MlJi^CLF.S. 



5. Tlie zygornnticus, tho presence of whicli is coiistanf in all species. 



6. The small zijgomaticus, repr. sonted in tlie Horse by only the small oblique fascicultw 

 sometiiued found bene;ith the zygoniaticus. 



The small zygouiaticus and ihe two elevators of the lips are lachrymal muscles ; by their 

 siniultaueous oontravtion they express discontent and melancholy. The zygoinaticus, on tlie 

 contrary, is the muscle of laughter; it draws the commissures of the lips outwards. 



7. The caninus, or dilator naiis lateralis of animals, is attached beneath the infra-orbital 

 foramen, and terminates in the skin of the upper lip. 



8. The risorius of Santorini. 



9. The muscle of the chin (mento-lahialis). 



10. The myrtiformis, or middle anterior of Bourgelat. 



The other facial muscles of Man, whose analogues it is difficult or impossible to find in 

 animals, are : — 



11. The triangularis of the lips, which is inserted into the anterior face of the inferior 

 maxilla, and is carried upwards tu the commissure of the lips. By its cxjutraction it gives the 

 face an expression of melancholy or contempt. 



12. The quadratus menti, which, after been attached to the maxilla within the mental 

 foramen, passes upwards on the skin of tiie lower lip, which it depresses, and thus contributes 

 to the expression of fear or dismay. 



13. The transversal is nasi {comj^re^sor nasi), a muscle which is fixed into the supermaxilla 

 and on the bridge of the nose, where it is confounded with the opposite muscle. 



14. The dilator of the ala of the nostril, a very small triangular fasciculus applied to the 

 external part of tlie nostril, which, by contracting, it elevates. 



3. Muscles of the Lower Jaw. 



There is nothing remarkable to be noted in the masseter, temporal, or pterygoid muscles. 

 The upper belly of the digastricus is not attached directly to the inferior maxilla, as it is in 

 Solipeds. 



4. Hyoideal Muscles. 



These are only three in number: — 



1. The niylohyoideus. 



2. The stylo-hyoideus, which commences at the styloid process of the temporal bone, and 

 shows a ring for the tendon of the digastricus. 



3. The geniohyoideus. 



We do not find in Man the occipito-styloideus, kerato-hyoideus, or the hyoideus-trausversus. 



Axillary Region. 



Tills comprises two muscles, pairs, placed beneath tlie sternum, in the axilla 

 which terminate on the anterior limb. These are the sitperjicial and deep 

 pectorah} 



Preparation.— \. Place the animal in the first position. 2. Unfasten one of the forelimbs, 

 and allow it to hansr, so as to sepnrate it from the opposite one. 3. Remove tlie skin with 

 care, and dissect, on the side corresponding to the detached limb, the two niuscles which furm 

 the superficial pectoral. 4. Prepare the deep pectoral on the opposite side. To do this, 

 remove tiie panniculus cautiously, so as not to injure the muscle about to be examined ; divide 

 the buperficial pectoral transversely, and turn back the cut purtioiis to the right and left; divide 

 also the mastoido-humeralis and cervical trapezius near their insertion into the limb, and 

 reflect them upon the neck. 



1. Superficial Pectoral (Pectoralis Anticus and Transversus) 

 (Figs. 174, 9, 10; 175, 3). 



Synonyms. — Muscle common to the arm and foTe&rm— Bourgelat. Pectoralis mngnus of 

 Man. (Pcrcivall and l.eyli describe three pectorals, others four; but, as will be seen in this 

 work, the two pectorals are each divided into two portions, which, for practical purposes, agrees 

 with those who describe four. This muscle is the Pectoralis transcerms of Percivall. Leyh 



' For a justification of tiie employment of these new denominations, see the note at p. 230. 



