CRANIAL SYMPATHETIC GANGLIA IN THE RAT 



193 



of the ramus palatinus IX. Kuntz ('13) has derived the otic 

 ganglion of the pig from the Gasserian ganglion and the rhomb- 

 encephalic wall. Kuntz states that the otic ganglion is well devel- 

 oped before there is any trace of a ramus palatinus IX. In the 

 rat this is certainly not the case. In 5.5-mm. embryos of the 

 gray rat (fig. 13) the first trace of the otic ganglion is to be found 

 as an enlargement in the growing tip of the ramus palatinus IX. 

 In fourteen and one-half day embryos of the albino rat, a large 



Fig. 13 Rat embryo (gray), 5.5 mm., Zenker's fluid, 

 ganglion; marked thickening at tip of ramus palatinus IX. 

 X 333. 



Anlage of the otic 

 Projection drawing, 



ramus palatinus IX is present, and a few scattered neuroblasts 

 (fig. 14) are present among its terminal fibers. The ramus 

 palatinus IX ends immediately below the ganglion geniculatum 

 VII well posterior to the Gasserian ganglion. No evidence has 

 been found for a migration of cells from the geniculate ganglion 

 into the anlage of the otic ganglion. I am unable to reconcile 

 my observations on pig embryos with the statement of Kuntz. 

 It is difficult to judge when, exactly, he would consider the otic 

 ganglion as 'well established.' Since his first descriptions of the 

 anlage of the otic ganglion are of pig embryos of from 12 to 15 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 31, NO. 3 



