io 4 STUDIES IN THE EVOLUTION OF ANIMALS 



spine, and on the abdomen, the rosettes coalesce into solid blotches, 

 while on the flanks and shoulders they do not. This fusion and 

 dispersion are evidently under the control of the nerve-centres, 

 where modifications originate, and are only made appreciable by 

 modified markings on the skin. 



But, really, why the rosettes remain as rosettes on the flanks, 

 and why they are dispersed on the shoulders of the Jaguar, while 

 they coalesce and form solid blotches along the spine and other 

 parts, I am unable to make out. 



Prof. H. B. Orr l says : ' Any single nervous reaction, in a 

 connected and often repeated series, does not disappear the instant 

 its original stimulus is withdrawn. It will last for some time after- 

 wards under the influence of association with the rest of the series. 

 Eventually, however, it must disappear, sooner or later, according 

 to the firmness of the association.' 



In the Jaguar and Leopard it would appear that the nervous 

 action is very late in disappearing, although they have been running 

 on parallel lines with Lions and Pumas for thousands, and, may be, 

 millions of years. They afford us an example of the persistence 

 of influence, although the stimulus may have been withdrawn ages 

 ago, while in Lions, Pumas, and others the markings have almost 

 wholly disappeared. 



It has been stated 2 that, at the Marine Laboratory of Plymouth, 

 experiments on the under surface of flat fishes have been made by 

 means of mirrors reflecting light from below. The under surface of 

 the fish first became spotted, then the spots amalgamated, and 

 finally the entire under-surface became dark. Photographs of 

 the different stages have been taken. 



According to Prof. Lodge, light is electricity, and experiments 



1 A Theory of Development and Heredity, p. 199. 



2 Chambers' s Jotirnal to\ August 26th, 1893, P- 54 1 - 



