PROCEEDINGS 



OF THE 



ROYAL PHYSICAL SOCIETY 



SESSION CXXXIV. 



I. Morphological Variations in Vipera berus. Size and 

 Scaling. By Gerald Leighton, M.D., F.E.S.E. 



(Received 10th October 1904 ; read 24th October 1904.) 



It is an axiom in zoological classification that morpho- 

 logical characters alone are to be taken into consideration, 

 and in the classification of serpents the characters utilised 

 for this purpose are the number and arrangement of the scales 

 of the body. By this means alone are specific characters 

 determined. It matters not what colour the reptile may 

 be, apparently even it is of no consequence if the colour is 

 constant in the two sexes, even the actual size to which the 

 reptile grows is thrust on one side as of no importance, 

 provided only that the scaling arrangements conform to the 

 type laid down as specific. A more artificial and un- 

 naturally restricted way of looking at an animal could hardly 

 be imagined. But nature does not trouble herself much 

 about specific characters, she leaves that to the morphologists. 

 The production of hard and fast lines by which species can 

 be separated, is not the object of natural life, but rather that 

 animals should vary and develop along those lines which 

 best enable them to meet the conditions under which they 

 have to exist. Those which do not thus vary are unhesitat- 

 ingly crushed out of existence. Hence, of course, such a 

 hard and fast line as is laid down for species of serpents to 

 conform to, must be honoured as much in the breach as in 



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