194 



FRED W. STEWART 



mm. in length, I should scarcely think that at this stage the otic 

 ganglion would be 'well established.' I have found a fairly large 

 ramus palatinus IX in 11 -mm. pig embryos and a smaller one in 

 an 8-mm. pig. There seems to be no trace of an otic ganglion, 

 nor have I been able to discover the structure before it was 

 noted as a diffuse collection of cells amid the fibers of the ramus 



G.N.V 



14 



Fig. 14 Rat embryo, 14| days. Early neuroblasts at tip of ramus palatinus 

 IX. Projection drawing from pyridine-silver preparation, X 500. 



palatinus IX, well posterior to the semilunar ganglion and ramus 

 mandibulars V. This is the condition noted in 15- and 16-mm. 

 pig embryos. In 17-mm. embryos the otic ganglion is quite a 

 well-marked structure, but has lost none of the diffuseness which 

 characterizes its earlier stages. The pig embryos whjch I have 

 examined in this connection form a rather close series (15, l(i, 

 17, 17.5, and IS mm . total length). The status of the otic 

 ganglion in the 18-mm. pig embryos resembles quite closely that 

 apparent in fifteen-day rat embryos (fig. 28). In the rat, nerve 



