III. 



On the Darwinian Hypothesis of Sexual 



Selection. 



II. — The Case of the Wall-Lizard. 



MESSRS. Hudson and Stolzman have already urged against 

 sexual selection that an argument based on a number of 

 cases selected from all quarters of the globe is obviously unfair. 

 I propose in the following to examine as a test case, and in the 

 briefest possible manner, some of the decorative variations of Lacerta 

 muralis, undoubtedly a " higher animal," in order to see what light 

 can thereby be thrown on this problem. 



As the vivid green or blue tints that sometimes adorn the body 

 of the male during the breeding-season cannot claim to be more than 

 " general brilliancy " as opposed to a " disposition of colours," I will 

 enumerate only, without admitting the justice of this distinction, 

 some less ephemeral embellishments. 



The lower surfaces, generally white, are often marked with a 

 delicate and symmetrical net-work, sometimes with a rich profusion, 

 of pink or yellow or black. The throat also varies. It is often 

 spotted half black and half red, and its colours occasionally contrast 

 with those of its under parts. The outer ventral scales generally 

 have a blue or black centrepiece, now and then a green one, and not 

 rarely the plates are alternately coloured blue and black, or green 

 and orange, etc. Or, again, the outer row of ventrals may be blue 

 and the next green. To show how complicated these patterns may 

 become, I will describe one male captured on the Filfla rock, near 

 Malta. The first row of ventrals on both sides of the body was blue 

 on the outer half and black on the other, the demarcation being 

 sharply defined, the next row was precisely similar, while the inner 

 two rows were of a rich ochre yellow. Thus there were five parallel 

 lines of regular and most attractive coloration. The throat and 

 collar of this specimen were symmetrically spotted with sky blue. 

 The large scittinu anale was jet black, and the soles of the feet spotted 

 black, with the single joints of the toes marked green.' Another 



' This is something like the var. Rasquineti, described by Bedriaga : " Beitrage 

 zur Kenntniss der Lacertiden Familie," p. 177. 



