Roth, Spinal Accessory Nerve. 



485 



quite small, while the fourth was large, its area exceeding con- 

 siderably that of the other three combined. The three small 



6*? Cerv 



T*C« 



8'^ Cexs 



l^Tho 



r-*ThoT. 



Description of Figure. Tran.sverse sections of the rami communicantes 

 of the sixth cervical to the second thoracic nerves in the dog. The outlines 

 were traced with a camera lucida ; the shaded areas represent white fibers and 

 the unshaded grey, but no attempt has been made to represent the actual number 

 of white fibers in the rami in which they are abundant, the eighth cervical nerve, 

 for example, containing more white rami than the sixth in which they are inter- 

 spersed with grey fibers. 



bundles were wholly composed of non-medullated fibers, but the 

 large one, though mainly non-medullated, contained imbedded 

 in its central portion a large number, at least 250, small calibered 

 medullated fibers. On superficial inspection, such a ramus 

 would undoubtedly appear to be a gray ramus since the white 

 fibers were almost entirely invested by the non-medullated ones. 

 The ramus of the seventh cervical nerve consisted of three 

 bundles, two of which were entirely grey, while the third con- 

 tained a few, about 25, medullated fibers. The eighth ramus 



