Variations in Spinal Nerves of Hyla a urea. 289 



With reference to the condition of nerve II. with regard to 

 the brachial plexus, we find the following results : — - 



Since nerve III. is increasing in thickness, we must regard 

 forms i., ii. and iii. as the most primitive, since they occur mostly 

 or only with the lower thicknesses of III ; forms iv. and v. on 

 the other hand occur not only with the four lower thicknesses of 

 III., but also with the live higher ones. The percentages are 

 somewhat irregular in their progression. 



%.'t 



Fig. 6 shows the positions of the nerves in these forms. In 

 form i. we find a connection of the coraco-clavicular with nerves 

 II. and IV., nerve II. thus taking a share in the brachial plexus. 

 This condition, however, was only found on one side of one 

 specimen and so might be regarded as an aberrant condition. 

 In form ii. we see the closest connection of II. with the 

 brachial plexus, this nerve being fused entirely or in part for 

 some considerable distance with III. In form iii. the connection 



