Sheldon, Nervus Tcninnalis in the Carp. 193 



(a) Two transverse series tliroiigii the bulbs and capsules in an 

 individual of 35 cm. length. 



(h) One longitudinal series through the bulbs and capsules of a 

 fish oO cm. long. 



(c) One transverse series through the hemispheres of an indi- 

 vidual 40 cm. in length. 



By these two methods one can easily demonstrate the peripheral 

 ganglion and the nucleus in which the fibers end centrally. 



As noted in the paper reported before the Association of Amer- 

 ican Anatomists, numerous scattered ganglionic cells are found on 

 the ventro-median side of the olfactory nerve about half way be- 

 tween the formatio bidbaris and the olfactory capsul^. Cells of 

 the same type are also found caudad to the glomerular region and 

 rostrad to the nasal capsules, diminishing rapidly in numbers, how- 

 ever, as one passes caudad or rostrad from the main group of cells. 

 It was also noted that Cajal preparations show coarse fibers which 

 can be traced from these cells rostrad to the olfactory mucous mem- 

 brane, where they are distributed to the epithelium with the olfac- 

 tory nerve fibers. 



The tract which forms the central course of the nerve is easily 

 distingaiished about half way between the caudal and cephalic ends 

 of the olfactory bulb on its ventro-median side. Here it is sur- 

 rounded by the medullated fibers of the tractus olfacto-lobaris 

 medialis as shown in Fig. 1, Rostrad of this point, however, it 

 is soon lost, as the medullated fibers either end or seek a new posi- 

 tion, leaving the nerve surrounded only by the unmedullated fibers 

 of the olfactory nerve. Scattered among these fibers in this region 

 are the cells of the peripheral ganglion. As the tract passes caudad 

 from the bull) it continues to hold its position on the ventro-median 

 aspect but migrates peripherally until it lies next the meninges, 

 surrounded on three sides, however, by the tractus olfacto-lobaris 

 medialis (Fig. 2). This relation holds throughout the length of 

 the olfactory cms (see Fig. 3). On reaching the cerebral hemi- 

 spheres the tract turns dorso-laterad through the tractus olfacto- 

 lobaris medialis to lie, for a time, between the latter and the radix 

 olfactoria medialis propria (Fig. 4). It holds this position for some 



