patch corresponds with the group of cervical nerves, the 

 shoulder patch with the brachial plexus, the side patch 

 with the nerves of the trunk, and the rump patch with the 

 sacral plexus. It may be further suggested that the 

 median crown patch of the head corresponds to the pineal 

 eye, a suggestion that is strengthened by the fact that it 

 is more or less obsolete in mammals, just as the pineal 

 gland is vestigial, whereas in birds, which are more 

 reptilian in structure, the patch is usually well defined. 

 At all events it is a median unpaired structure, as are the 

 pineal and the interparietal bone. 



Turning now to a more detailed consideration of these 

 pigment patches in sundry species of animals, we may 

 iirst examine a series of diagrams (Figs. 1-15) of the 



