NoRRIS, Nerves of Jiuphiiuna. 529 



lateral border of the brain (figs. 13 and 20). From this point to 

 the anterior end of the brain the emerging fibers constitute a 

 dorsal part of the olfactory trunk. A ventral smaller part is 

 formed by fibers that leave the more ventral glomeruli. Anteriorly, 

 before the nerve leaves the brain, the two portions have become 

 indistinguishably united; in fact there appears to occur an inter- 

 lacing of fibers. Other smaller roots join these tv^o main portions. 

 As the nerve passes into the nasal capsule (fig. 3) it is seen to con- 

 sist of about eight branches, arranged in two or three bundles. 

 The ventral branch in the more ventral of the three bundles passes 

 to Jacobson's organ (figs. 2 and 20) giving off also some branches 

 to the ventral olfactory epithehum. The nerve to Jacobson's 

 organ passes to the anterior lateral ventral border of that structure, 

 thence dorsally and posteriorly along its dorsal wall. The other 

 branches in the ventral group innervate the ventral olfactory 

 epithelium; the fibers of the middle bundle supply the median 

 wall of the olfactory epithehum; and the dorsal bundle goes to 

 the dorsal wall, except that immediately on entering the nasal 

 capsule one of the dorsal branches sends a large twig to the ventral 

 wall (fig. 20). It may be true that the branch innervating Jacob- 

 son's organ comes from the ventral portion (or root) of the nerve, 

 but it is certainly too small to contain all the fibers that arise by 

 that root. It will thus be seen that the condition in Amphiuma 

 contributes little in answer to the query whether or not there are 

 two morphologically distinct elements in the olfactory nerve. 



3. THE OPTIC NERVE. 



The account given by Kingsi^ey is confirmed throughout. 

 Myelinic sheaths are not in evidence. Sagittal sections show that 

 as the nerve leaves the brain a small ventricular diverticulum 

 reaches out to the point of emergence of the nerve, but apparently 

 the cavity has no peripheral extension. 



4. the eye-muscle nerves. 



Of these KiNGSLEY was able to find but one, the oculomoto- 

 rius. I find that the oculomotorius, the trochlearis and the 

 abducens nerves arise in the typical manner, but are much reduced 

 in size. The oculomotor nerve leaves the lateral wall of the anterior 



