74 



ALBERT KUNTZ 



6 mm. in length, the neural crest has already become differen- 

 tiated into ganglionic masses. At this stage the anlage of the 

 semilunar ganglion appears as a somewhat irregular mass of 

 cells lying in close proximity with the lateral surface of the 

 anterior region of the rhombencephalon and almost or quite in 

 contact with the ectoderm. As development advances the posi- 

 tion of this ganglionic mass is shifted ventrad until the entire 

 anlage lies ventro-lateral to the rhombencephalon in the region 

 of the pons. 



^.,4j^ 





Fig. 1 Drawing made from a wax reconstruction of the third and the fifth 

 cranial nerves in an embryo of the pig 27 mm. in length. Cil, ciliary ganglion; 

 Lin, lingual nerve; Ma, maxillary nerve; Man, mandibular nerve; Oc, oculo- 

 motor nerve; Oph, ophthalmic nerve; Ot, otic ganglion; S, semilunar ganglion; 

 Sph, sphenopalatine ganglion; Subm, submaxillary ganglion. 



In embryos of the pig 8 mm. in length, the semilunar ganglion 

 is quite definitely outlined. It still lies in close proximity with 

 the wall of the rhombencephalon. Its proximal surface is slightly 

 concave, while its peripheral surface is irregularly convex. The 

 entire mass, therefore, is already roughly crescentic in outline. 

 The fibers of the sensory root of the trigeminal nerve have already 

 penetrated the wall of the rhombencephalon and the motor root 



