SECTION VIII. THE MUSCULATURE 



For the study of the musculature in detail a fresh specimen 

 of R. catesbiana is desirable. If this is not feasible, the 

 dissection of the muscles of the leg (pp. 44-6) at least should 

 be completed, using the material already at hand. The 

 muscular system includes not only the muscles attached 

 to the skeleton but also the muscles of the viscera, skin, and 

 sense organs. The skeletal muscles alone will be considered 

 in this guide, and only the more prominent of these. The 

 advanced student is referred to Gaupp, where over one 

 hundred and fifty separate skeletal muscles are described. 

 In the description of the muscles, the term origin refers to 

 the relatively immovable attachment of the muscle, the 

 term insertion to the part moved. In dissecting the muscles, 

 they should be spread apart with the handle of the scalpel. 

 When the directions call for the cutting of a muscle, this 

 should be done by lifting it carefully and making an in- 

 cision through the middle (belly) of the muscle from 

 below. 



Skin a frog, exercising great care not to tear any of the 

 underlying structures. Place it on the dissecting board and 

 identify the folloiving muscles, commencing at the cephalic 

 end. Sketch as you dissect, showing the superficial muscles 

 at the right of the mid-line of your drawing, and the deeper 

 muscles at the left. Do not attempt to verify the insertions 

 and origins until you have identified the adjacent muscles. 



249. Temporalis. In front of the tympanum. Origin 

 from prootic and occipital: insertion on angulare. 



250. Depressor mandibulae. Behind tympanum. Ori- 



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