1903 Reptile Studies 305 



to offspring which have varied from their parents, simply 

 because all offspring do vary more or less from their 

 parents. They have thus become adapted to their environ- 

 ment, and given rise to a new species. .According to this 

 view, only a certain number of offspring possess the 

 advantageous variation, and they are selected to survive. 

 It only requires thai a male and a female each possessed 

 of the new character should pair, in order that it may be 

 possible for the variation to become permanent and intensi- 

 fied. It thus appears that some very profound modifications 

 may arise suddenly, as the result of this spontaneous variation, 

 and in such a case the intermediate stages may be non- 

 existent. We may represent the origin of the limbless 

 lizard on this view thus : — 



f Male (long limbs) ) 

 I Female (long limbs) J 

 I Female (long limbs) j P s I Female (short limbs, a spontaneous 



rMale (long limbs) „. . | Female (long limbs)/ m 



< >nffcni-inir -. . _ __ 



I Female 

 V. variati 



on conferring an advantage). 



If a similar variation arose in a male of the same or 

 another litter, and the two spontaneous variations paired, 

 the result would be — 



Male (short limbs) S ,,.,.,.., 



Female (short limbs) / ° ffs P rin S a short-limbed family, a new species. 



And similarly with other variations of kind or degree. 



This brief outline of the two main biological views on 

 this subject is merely intended to direct the attention of the 

 field naturalist reader to the explanations offered by science 

 to account for the origin of such an anomalous reptile as 

 the slow-worm is, as well as for the origin of species in 

 general. It merely touches the fringe of the greatest of all 

 biological subjects, and of necessity ignores all the numerous 

 sidelights which may be thrown upon it ; but it is hoped 

 that it may be just sufficient to induce readers to examine 

 the matter for themselves, and apply what they learn to the 

 species of animals in their own country. 



It remains to be noted what degrees of variation in the 

 matter of limbs are to be found existing at the present day 

 amongst lizards, which may be regarded as connecting links 



