272 E. VICTOR SMITH 



and irregular. Initial glomeruli were not observed, and implanta- 

 tion cones were seen only in spinal ganglia outside of the brachial 

 region. 



2. Cerebral ganglia 



The cerebral ganglia observed were the ninth, tenth, and Gas- 

 serian of the common domestic duck and of the domesticated 

 mallard. 



a. Ga7iglion of the ninth nerve. The glossopharyngeal ganglion 

 of the common domestic duck measured 1 mm. wide and the 

 cells extended along the ganglion for 1.5 mm. The cells are 

 much more numerous at the periphery than at the center, but 

 they are not uniformly distributed at all parts of the periphery. 

 One surface bulges into a pocket in which the cells are more numer- 

 ous than at the opposite side. In the center the cells are com- 

 paratively few, and are divided into rows by the large bundles of 

 fibers. In a section cut from the widest part of the ganglion 360 

 were counted. 



As to size, one of the largest cells was 39 by 54 /z; one of the 

 smallest was 19 by 39 n. The average size is about 30 by 39 n, 

 and there are regular gradations between the largest and the 

 smallest. 



The major diameters of nuclei were from 8 to 13 n, and the 

 minors from 8 to 11 m- The processes in nearly all cases emerged 

 without twists or turns and few implantation cones were observed. 



In the mallard the ganglion of the ninth nerve is not so large 

 nor is it bulged on one surface as in the common domestic duck. 

 The arrangement of the cells in the ganglion is similar in both 

 cases, except that in the mallard they are more evenly distributed 

 about the periphery. The cells are smaller and more uniform in 

 &iz,e than in the common duck. The largest measured 27 by 

 33 ju; the smallest 16 by 19. The average of the cells is about 

 28 ju long and 23 wide. The cells were mostly elliptical in shape, 

 some were rounded and many were irregular, but the irregularity 

 is not due to the crowding of neighboring cells. 



b. Vagus ganglion of the mallard. The vagus ganglion is quite 

 small as compared with that of the common domestic duck. It 



