HISTOLOGY OF SENSORY GANGLIA OF BIRDS 267 



oppositi-polar (fig. 34), An occasional departure from the oppo- 

 siti-polar condition occurs, but in no instance is there any near 

 approach to the unipolar. The cells are nearly uniform as to 

 shape and size, the shape being oval, with conical poles from which 

 emerge the processes. The largest cells have a major diameter 

 that averages 33 ix and a minor that averages 18, while the smaller 

 cells have major diameters varying between 14 and 20 /x and 

 minors varying between 10 and 12. 



The nuclei are round to elliptical in shape. In the larger cells 

 the major diameters of the nuclei vary between 5 and 8 ii, while 

 in the smaller cells the major diameter vary between 3 and 5 /x. 



The peripherally directed process was larger than the one 

 centrally directed but there was less difference of size than in 

 the branches of the sensory cells of the other ganglia. The proc- 

 esses for the most part followed a direct course as they issued 

 from the cell, but as shown in figure 36, some of them exhibit an 

 initial glomerulus of a single loop. These glomeruli were found 

 as frequently on the centrally directed processes as on the distally 

 directed ones. 



C. SENSORY GANGLIA OF THE GOOSE 



1. Spinal ganglia 



The only spinal ganglia of the. goose carefully studied were 

 from the cervical region. These ganglia measure about 3 mm. 

 in length and are large as compared with the corresponding ganglia 

 of the other birds. The ganglion cells are distributed largely in 

 clusters with a variable number of cells and separated by areas 

 free from cells. 



The cells vary considerably in size and shape. The majority 

 are elliptical, some are rounded, others are irregular, and a few 

 are elongated. One of the largest cells observed was 50 by 36 /x, 

 one of the smallest was 19 by 14. Some of the elongated ones 

 varied much from the ordinary proportions, one of these having 

 a major diameter of 74 yu and a minor diameter of only 16. 



The predominating form of nucleus is elliptical, a smaller num- 

 ber only being rounded. They vary in major diameter between 

 8 and 15 /x and in minor between 5 and 13. 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 14, NO. 2 



