32 DISSECTION OF THE CAT 



The following muscles of this group can best be 

 seen after the dissection of the muscles of the 

 fore-leg and shoulder. 



4. The External Intercostal Muscles are the outer 

 muscular layers extending between the bony ribs. 

 Their fibres run backward and downward. (Plates 

 III. and IV.) 



5. The Internal Intercostals are muscular sheets 

 lying under the former, their fibres running back- 

 ward and upward. They are covered by the ex- 

 ternal intercostals, except between the cartilagi- 

 nous ribs. (Plate III.) 



6. The Serratus Posticus Muscle arises from the 

 fascia of the mid-dorsal line, and is inserted by 

 digitations on the eighth, ninth, tenth, eleventh, 

 and twelfth ribs. A dense membrane, the verte- 

 bral aponeurosis, is continuous with the muscle an- 

 teriorly. This membrane passes forward between 

 the muscles of the back and those of the shoulder, 

 and covers over the erector spince muscles, which 

 fill the groove on either side of the neural proc- 

 esses of the vertebras. (Plate III.) 



MUSCLES OF THE FORE-LEG AND SHOULDER. 



I. The Cephalo-liumeral or Anterior Trapezius Muscle 

 takes its origin from the back of the skull and the 

 mid-dorsal line of the neck. It is very long and 

 passes downward, covering the anterior part of 

 the fore-leg, to its insertion on the coronoid proc- 



