SKELETAL MUSCLE 



IIQ 



chymal cells, but Bardeen and Warren Lewis consider that " the myo tomes 

 play no part whatever in the origin of the musculature of the limbs." 

 Moreover, Lewis states that " the idea that myotomes play a role in the 

 origin of the muscles of the head must be abandoned." A radical differ- 



C 



D 



FIG. 108. TRANSVERSE SECTIONS THROUGH THE MIDDLE OF CERTAIN SOMITES IN SUCCESSIVELY OLDER 

 CHICK EMBRYOS. A, B, AND C., THROUGH ONE OF THB SECOND PAIR OF SOMITES IN EMBRYOS OF 

 NINE, FIFTEEN, AND TWENTY-FIVE SEGMENTS RESPECTIVELY: D, THROUGH ONE OF THE FORTY-FOURTH 

 PAIR IN AN EMBRYO OF FIFTY-TWO SEGMENTS. X 230. (Williams.) 



ao., Aorta; d, dermatome; m, myotome; m. t., medullary tube; n, notochord; s, sclerotome; z, angle at which 



the myotome develops. 



ence in the source of smooth and striated fibers has therefore not been 

 demonstrated, but the two forms of muscle develop very differently. 

 The myoblasts which produce striated muscle are found in the midst 



