132 CHAKLES BROOKOVER 



A few cells have been found in the sections so far made of the 

 olfactory region of the nasal mucous membrane with its subja- 

 cent structures as far centrally as the cribriform plate. The 

 number discovered is not as great as it would seem from sections 

 of the fetuses above mentioned should be the case, since the num- 

 ber of cells attributable to the nervus terminalis peripherally in 

 these fetuses appear to outnumber those within the cranial cav- 

 ity. From the distribution of the cells of the larger of these 

 fetuses it would appear that the cells are much scattered and 

 that they are to be found in small numbers along many of the fila 

 olfactoria, those distributed to the lateral nasal mucosa as well 

 as those to the region of the nasal septum. From a study of a 

 fetus which measures over five inches head-rump length, it is evi- 

 dent that the cells recognized as nervus terminalis cells extend 

 beyond the olfactory into the respiratory region along the sep- 

 tum, and curiously enough, most of the cells noticed were found 

 along a ramus traced anteriorly and ventrally to what was be- 

 lieved to be the rudimentary organon vomeronasale. That these 

 cells should be found in the respu'atory region and more numer- 

 ous in the strand of fibers to Jacobson's organ corresponds with 

 the condition found by Huber and Guild ('13) in the rabbit. 



After some futile search for the central course of the nervus 

 terminalis in close juxtaposition to the olfactory tracts we found 

 its intra-cranial course posterior to the olfactory bulbs to lie over 

 the middle of the gyrus rectus as shown in figure 1. A rectangu- 

 lar piece of the pia mater stripped from this region of the gyrus 

 rectus has never failed to reveal the fibers of the nerve in all the 

 well preserved brains examined. In some brains where the 

 bundle is well compacted into a single strand it is possible to 

 dissect the nerve out in situ with the aid of a small magnifier. 

 As a general thing we have found the fibers to be broken up into 

 two or three strands and especially is this the case at its anterior 

 extent near the olfactory bulbs and posteriorly near the medial 

 olfactory striae. The fibers of the nerve seem to have passed 

 over from the dura to the outer surface of the pia mater in the 

 region of the olfactory bulbs and to continue posteriorly exter- 

 nal to the pia, but beneath the larger blood vessels of the arach- 



