HISTOLOGY OF SENSORY GANGLIA OF BIRDS 275 



The cells are mostly elliptical in shape, a number are rounded, 

 and the remaining cells are irregular. The greater diameters 

 vary between 14 and 55 ^ and the lesser between 11 and 41 n. 

 The nuclei are round to elliptical, with the larger nuclei in the 

 larger cells. The processes, where observed, issued without twist 

 or initial glomerulus. 



c. The Gasserian ganglion. The Gasserian ganglion of the 

 turkey is also small in comparison with that of the duck and goose. 

 It 'is about the same size as the Gasserian in the chick. The 

 cells are much closer together than in the ganglia of the other 

 large birds, and are arranged in groups having one to three rows 

 of cells. The rows are usually of considerable length. The 

 cells are nearly uniform in shape, being mostly elliptical with 

 a few rounded and irregular forms. The major diameters range 

 between 25 and 82 n, and the minor between 14 and 50 /x. The 

 nuclei are round to elliptical, the majority being rounded. No 

 deviation from the usual way in which the processes issue from 

 the cells of other birds was observed in the Gasserian of the turkey. 



F. SENSORY GANGLIA OF THE PIGEON 



1. Spinal ganglia 



In the pigeon the ganglia of the brachial and lumbo-sacral 

 regions are much larger than the other spinal ganglia, and those 

 of the brachial region are considerably larger than those of the 

 lumbo-sacral. 



In the brachial ganglia the cells are somewhat more numerous 

 about the periphery than in the central part. There is a decided 

 tendency toward the arrangement of the cells into elongated 

 groups consisting usually of single rows of cells. Here again, is 

 seen the division of cells into two classes, large and small. The 

 large cells are not numerous but are decidedly larger than the 

 others. One of the average sized large cells was 35 by 44 fx. 

 This cell had a rounded nucleus 14 /j. in diameter. An average 

 cell of the smaller size is about 30 ^t long and 19 broad, with a 

 nucleus of 7 by 11 /j,. Most of the cells are elliptical, a few are 

 rounded and irregular. The nuclei are relatively large and are 

 round to elliptical in shape. 



