80 ALBERT KUNTZ 



Ciliary ganglion 



In embryos of the pig 8 mm. in length, as shown in parasagittal 

 section in figure 4, the oculomotor nerve terminates among the 

 closely aggregated mesenchyme cells which constitute the anlage 

 of the posterior rectus muscle. A few cells of nervous origin 

 which have advanced peripherally along the path of this nerve 

 may be observed aggregated at its growing tip (fig. 4, Cil). These 

 cells, doubtless, constitute the anlage of the ciliary ganglion. 



In embyros 12 to 14 mm. in length, the oculomotor nerve has 

 advanced farther peripherally into the region of the future orbit. 

 The analge of the ciliary ganglion now appears as a small aggre- 

 gate of cells lying in more or less intimate contact with the oculo- 

 motor nerve a short distance posterior and ventro-mesial to the 

 optic cup (fig. 6, Cil). In parasagittal sections of an embryo 

 14 mm. in length which cut the ophthalmic nerve longitudinally, 

 oblique sections of the oculomotor nerve may be observed distal 

 to the periphery of the semilunar ganglion and between the 

 ophthalmic and the maxillary divisions of the trigeminal nerve 

 (fig. 6, Oc). In such sections, as shown in figure 6, the anlage 

 of the ciliary ganglion lies in close proximity with the path of 

 the oculomotor nerve. Between this anlage and the ophthalmic 

 nerve, a few small groups of cells obviously of nervous origin 

 may be observed lying in the mesenchyme (fig. 6, MC). These 

 cells, doubtless, represent nervous elements advancing from the 

 ophthalmic nerve toward the anlage of the ciliary ganglion. In 

 one instance two of the cells contained in one of these groups 

 were obviously neuroblasts. One of these cells is illustrated in 

 figure 5, A. A few neuroblasts were observed also in the oph- 

 thalmic nerve. The presence of a slight accumulation of nerv- 

 ous element at the ventral side of the ophthalmic nerve and of 

 groups of similar cells lying in the mesenchyme approximately 

 in a direct line from this point toward the anlage of the ciliary 

 ganglion warrants the conclusion that cells which advance 

 peripherally from the semilunar ganglion along the fibers of 

 the ophthalmic nerve deviate from the course of this nerve and, 

 advancing through the mesenchyme, enter the anlage of the 



