HISTOLOGY OF SENSORY GANGLIA OF BIRDS 269 



merous at the proximal than at the distal end. Nerve cells were 

 found distributed for a considerable distance along the path of 

 the tenth nerve, but in the ninth nerve no cells were found beyond 

 the place of its emergence from the ganglionic mass. 



Although cells were abundant in that part of the ganglionic 

 mass through which the fibers of the ninth nerve passed, yet 

 processes from these cells could not be traced into the ninth nerve, 

 but many could be traced from the cells into the tenth nerve. 

 Only a few cells in the vagus ganglion approached the rounded 

 form. Nearly all were much longer than broad and the very 

 large cells were frequently more than twice as long as broad. 

 The prevailing shape is elliptical, but there were a number of 

 club and pear-shaped forms. There were very few that showed 

 much irregularity of outline, there being sufficient room for the 

 cells without crowding. Figure 39 shows one of the greatest 

 irregularities observed. 



The ganglionic cells of the vagus of the goose are remarkable 

 for their great size (fig. 39), being much larger than the cells seen 

 in any other bird, larger even than those of the Gasserian ganglia 

 of the same bird. The cells measured ranged in length between 

 33 and 102 /x, and in breadth between 25 and 48 /x. The average 

 length of the cells is between 55 and 60 ij. and the average breadth 

 between 33 and 35. 



The nuclei have clearly defined boundaries and are mostly 

 round to elliptical. The larger cells have the larger nuclei, but 

 the increase in the size of the nucleus is not proportional to the 

 increase in the size of the cell. The largest nucleus observed 

 measured 12 by 16 ju and the smallest 9 by 11. 



The main process usually issues from one pole of the ceil and 

 is directed toward the distal end of the ganglion, but numerous 

 exceptions were observed. The processes are large and emerge 

 from the cell in a straight line or with but slight deviation from 

 the straight course (fig. 39) . No initial glomerulus was observed, 

 but in one cell the process was quite twisted. ImplantatioA cones 

 were not observed. 



The capsules of the cells were clearly pictured (fig. 39). They 

 were quite delicate and had a number of clearly defined nuclei 



