MUSCULAR SYSTEM 



831 



for the purpose of opening and closing the clefts and also the mouth. In 

 the higher forms many of these muscles have disappeared although some 

 do retain their connection with the hyoid. 



Visceral muscles are often divided into two sets according to their 

 derivation, as some develop from muscles which originally ran in a 

 transverse (circular) and others from those which ran in a longitudinal 

 direction. 



The epibranchial muscles, the .sub-spinals and interbasales (which 

 lie in the dorsal part of the branchial region), and the coraco-arcuales (in 



genioglossus 

 styloglossus 

 geniohyoid 

 hyoglossus 

 constrictor pharyngis 



thyrohyoid 

 cut edge of 

 sternomastoid 

 sternohyoid 

 sternothyroid 

 cleidomastoid 

 cut edge of 

 clavotrapezius 

 sealeries 

 biceps brachii 

 subscapularis 

 teres major M. 



mandible 

 molar gland 

 masseter 

 digastnc 

 mylohyoid 

 parotid gland 

 ibmaxillary gland 

 lymph glands 



clavotrapezius 



external jugular vein 



clavobrachialis 



pectoantibrachialis 



long head of 

 the triceps 



tiansversus costarum 

 serratus ventralis 



long head of 

 the triceps 



external oblique 



Fig. 468. 



Ventral view of the anterior part of a cat to show the muscles. All dermal 

 muscles have been removed. Superficial muscles on the right side, deeper layer of 

 muscles on the left side, after removal of the pectoral muscles, sternomastoid, 

 mylohyoid, and digastric. The nerves and blood vessels which cross the axilla have 

 been omitted. The epitrochlearis is also called extensor antibrachii. From Hyman's 

 "A Laboratory Manual for Comparative Vertebrate Anatomy," by permission of 

 The Chicago University Press.) 



