HYPOGLOSSAL GANGLIA OF PIG EMBRYOS 



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to the ganglion nodosum of the vagus {gang, nodos.) a small 

 bundle of fibers is given off to form the peripheral portion of the 

 spinal accessory {XI'). 



Two embryos of 8.5 mm. showed the structure of fig. 2. In two 

 others of 9 mm. no distal root has developed from Froriep's 



gang 

 sap. 



Fig. 4. Dissection of a 13 mm. pig to show a seiies of hypoglossal ganglia and 

 two double cervical ganglia. 



ganglion (fig. 3). The first cervical is not distinctly double and 

 shows no connection with the second cervical ganglion. The prox- 

 imal roots are longer, however, and the neural crest near the jug- 

 ular ganglion is better differentiated. Two flat distal strands of 

 mixed cells and fibers pass down parallel to the spinal accessory 

 fibers and enter the vagus. 



This stage brings out three important points: (1) the first 

 cervical ganglion frequently originates as a double structure; (2) 



