434 APPENDIX. 



In transecting a muscle, work under it completely from one edge 

 to the other (except in case of very wide muscles), then introduce 

 the scissors or scalpel, and cut it by a smooth clean cut. Always 

 leave the entire origin with one-half of the muscle, the entire inser- 

 tion with the other half. 



The student must be prepared to find in some cases considerable 

 variations from the conditions described. The descriptions attempt 

 to give an account of the usual structures, but specimens showing 

 no variations whatever are undoubtedly rare. 



DIRECTIONS FOR DISSECTING THE MUSCLES OF THE CAT. 

 I. THE SKIN-MUSCLES (pp. 93-96, and Fig. 62). 



These will perhaps not usually be dissected. If they are to be 

 dissected, proceed as follows: Make a ventral median longitudinal 

 incision of the skin from the cranial end of the manubrium to a 

 point opposite the crest of the ilium. Connect the cranial end of this 

 incision with the middle of the lambdoidal ridge by a similar incision 

 through the skin. Make another incision from the manubrium to 

 the spinous process of the thirteenth thoracic vertebra. Connect 

 the caudal end of the first incision by an oblique cut with the root of 

 the tail. Make another incision from the convexity of the knee- 

 joint along the fold of skin which connects the hind limb and body, 

 as far as the incision which leads to the root of the tail. Make an 

 incision surrounding the base of the forelimb. Now reflect these 

 flaps one at a time, working in general from the ventral side toward 

 the dorsal middle line. Take great pains not to take up the thin 

 skin-muscle with the skin. In this way all of one side of the body 

 will be uncovered. The cutaneus maximus (Fig. 62, b) and a part 

 of the platysma (Fig. 62, a) will be thus exposed. Read and verify 

 the descriptions of these muscles (pp. 93-96). The cranial portion 

 of the platysma cannot be seen at this stage, but should be dissected 

 in connection with the muscles of the face. 



II. SUPERFICIAL MUSCLES OF THE FACE AND HEAD (pp. 96-107, and 

 Figs. 63 and 64). 



These will perhaps not usually be dissected by the student. 

 They should be studied on a well -dissected laboratory preparation, 

 if possible. If they are to be dissected, this should be done if 

 possible on a fresh specimen, as it is very difficult to dissect them 

 on preserved material. Proceed as follows: 



The skin should be removed with care from the sides and top of 

 the face and head, without injury to the external ear. 



1. The platysma (p. 95, and Fig. 62, a). Determine its 

 cranial attachments. 



2. The intermedius scutulorum (p. 96, and Fig. 63, a). 



