274 



C. W. PRENTISS 



it is not possible to distinguish an anterior cranial series belonging 

 to the vagus complex, and a pre-cervical group of spinal ganglia 

 as maintained by Streeter ('04) ; (6) the connection between the 

 chain of ganglia and the vagus is not as marked in most cases as 

 Lewis figures, and when well developed represents a persistence 



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Fig. 6. Dissection of a 17 mm. pig showing three distal roots passing from the 

 hypoglossal ganglia to the ventral roots of the hypoglossal nerve and a fourth 

 incomplete root. 



of the ganglionic crest — a persistence common also to the spinal 

 ganglia; (7) the spinal accessory root could be traced back to the 

 sixth cervical ganglion. 



Stage 4- 17-18 mm. Further elongation of the nerve roots is 

 accompanied by a differentiation of the hypoglossal ganglia 

 greater than at any other stage (figs. 6 and 7) . The ganglia are 

 relatively smaller but a continuous cord of cells may still be traced 



