438 O. LARSELL 



yet reached the same degree of development. This view appears 

 to be favored by the extremely crowded condition of these cells 

 ^^■ithin the ganglia. This would appear to result in a reduction 

 both of the amount of space and of nourishment which the indi- 

 vidual cell may obtain, thus retarding its growth. The fact 

 that the larger cells were found near the periphery of the ganglia, 

 where there would appear to be space for greater expansion of 

 the cells during growth as well as more abundant nourishment, 

 may account for their larger size at this stage of development. 

 There were also cells of intermediate size between the two 

 groups, but these were not so numerous as the cells of either 

 group. 



In the gasserian ganglion (fig. 11) of the older stages the number 

 of small cells was not so great as in the spinal ganglia, but here 

 also some were present, as the figure indicates. 



The sympathetic chain ganglia of the older stages, as in the 

 younger, contained cells of rather uniform size and appearance (fig. 

 12). Two or three processes were observed on most of the cells 

 which were examined on this point. The nuclei were smaller than 

 those of the small spinal ganglion cells, showing an average size 

 for fifty cells of 6.2 fx, as compared with 7.3 ^ for the latter type. 

 The relative amount of cytoplasm surrounding the nucleus ap- 

 peared to be about the same in the two types. No difference in 

 the size of the peripherally located cells, as compared with those 

 situated nearer the centers of the sympathetic ganglia, was 

 observed. 



The ciliary ganglia showed two groups of strongly contrasting 

 cells. Without entering into a detailed description of this 

 ganglion or attempting to review the large amount of litera- 

 ture w^hich has accumulated concerning it, the present pur- 

 pose will be served by calling attention to Carpenter's ('06) 

 excellent study of it in the chick and adult fowl. He finds two 

 distinct sizes of cells. The smaller cells were arranged in a 

 definite group on the dorsal side of the ganglion. This group 

 composed about one-third of the entire mass. 



A similar group of small cells (fig. 13, A) was present in many 

 of the turtle embryos, but not in all, studied by the present 



