400 NATURAL SCIENCE. Dec,, 



" while the similar individuals breed together."^ But I venture to think 

 an easier explanation lies at hand. The " distinctness " of the adults 

 may be referred to what is a common enough phenomenon among 

 animals and plants, namely, that the offspring of two varieties is not 

 intermediate between them (or only so while young), but assumes 

 the character of one or the other parent form. As to the contests, 

 they take place indiscriminately between the individuals of either 

 variety and are generally provoked, no doubt, by disputes over food. 

 This is a vera causa for enmity between individuals as between races, 

 when brought into contact by identity of requirement ; but there is 

 no reason whatever why, in the case like the present one, the indi- 

 viduals of var. a should be more hostile to those of var. h than 

 towards each other. As a rule, pugnacity in lizards is an individual 

 matter, but L. muralis, as a species, is certainly more pugnacious than 

 many. Two males may often be seen rushing at each other without 

 the slightest apparent reason. Perhaps the feeling of rivalry is also 

 strong; but I should like to say, in order to avoid misunderstandings, 

 that the female takes no art or part in the contests of the males — it is 

 quite by accident if there happens to be a female spectator — and 

 even supposing some form of courtship to be decided by wager of 

 battle, she would be compelled to accept the victor, however 

 distasteful his style of ornamentation might be to her preconceived 

 notions of beauty. 



The whole question of sexual selection, therefore, with this 

 species, and innumerable others, turns on this simple matter of 

 observation. I submit that wherever such promiscuity among the 

 individuals exists as with L. muralis, it is a contradiction in terms to 

 state that decorative colours have been evolved through the choice of 

 particular males by the other sex. 



I might add that the same difficulty of analogous variability, 

 previously mentioned, presents itself in another shape. The wall- 

 lizard of the islands of Malta and Seriphos is apt to assume a brilliant 

 yellow patch on the throat. Unless this is adaptive in some way it 

 would imply a curious coincidence in taste on the part of the females 

 of these widely-separated races. The vav. nigviventvis, a recent form, 

 whose colour cannot be adaptive in any sense of the word, occurs at 

 Genoa and at Algiers : can it be presumed that an identical change of 

 female aesthetic conceptions has taken place in these different 

 localities ? The same applies to the vav. Jiaviventvis. 



There is, lastly, a difficulty on what may be termed mechanical 

 grounds. I have purposely described the detailed colour-pattern 

 on the lower surfaces of a specimen from Malta. How is the female 

 to see it? 



1 Eimer, " Organic Evolution," translated by J. T. Cunningham, p. 42 ; "Variiren 

 der Mauereidechse," 1881, p. 79. The author attributes a certain influence in the 

 colour development of this species to sexual selection. " Zool. Studien auf Capri," 

 ii., passim. "Variiren etc.," pp. 22, 27, 15S. 



