CRANIAL SYMPATHETIC GANGLIA IN THE PIG 89 



superficial petrosal nerve can be found. Likewise, it is highly 

 improbable that any cells are contributed to the otic ganglion by 

 way of its sympathetic root. 



Submaxillary ganglion 



The submaxillary ganglion arises as an accumulation of cells 

 of nervous origin associated with the lingual division of the 

 mandibular nerve. In embryos of the pig 13 to 16 mm. in length, 

 the mandibular division of the trigeminal nerve is already differ- 

 entiated into its component parts. In parasagittal sections of 

 embryos at this stage, the lingual and the inferior dental divisions 

 of the mandibular nerve may be traced into the mandibular 

 region. The lingual nerve passes lateral to the pharynx and 

 beneath the root of the tongue where it may be traced anteriorly 

 in the floor of the oral cavity well toward the tip of the mandible. 

 Just beneath the root of the tongue the lingual nerve gives rise 

 to several slender branches which grow ventro-mesially. Cells 

 which advance peripherally along the lingual nerve wander out 

 along one or more of these slender branches and become aggre- 

 gated to give rise to the anlage of the submaxillary ganglion. 

 The anlage of the submaxillary ganglion, therefore, arises in 

 contact with one or more of these slender branches and is removed 

 by only a short interval from the path of the lingual nerve. 



The relationships of the submaxillary ganglion to the lingual 

 nerve, in the early stages of development, can not be well illus- 

 trated in drawings made from sections because of the somewhat 

 irregular course of the lingual nerve and its branches. Figure 14 

 represents a parasagittal section passing through the anlage of 

 the submaxillary ganglion in an embryo of the pig 16 mm. in 

 length. The ganglionic anlage in this instance is removed from 

 the lingual nerve (not shown in the section) by a short interval 

 and is located at the extremity of a slender branch along which 

 its component cells have obviously wandered out from the nerve- 

 trunk. 



In embryos 20 to 21 mm. in length, the ganglionic mass has 

 increased materially in size and lies in contact distally with a 



