INTRODUCTION. 



with either strice, punctures, or ruguloeities, and is variously 

 coloured ; it is often smooth and glabrous, but, frequently, also 

 clothed with spines, bristles, hairs, or downy pubescence, of 

 different colours ; forming a distinctive pattern, which usually 

 follows the converging direction of the various indentations. 



In numbers of male spiders, of various families and genera, 

 the caput (especially the ocular region) is liable to excessive, and 

 often quite eccentric developement. This is carried to, perhaps, 

 its greatest extent, among our indigenous spiders, in the genus 

 Walokenadra, where the eyes are thus thrust up (as it were) 

 on more or less considerable, and variously shaped elevations 

 and eminences (pi. iv., figs. 3 and 4). The females present little 

 or no trace of this excessive development. If it be true that no 

 natural development can exist, which is not of some benefit to 

 the possessor, and which has not been produced by natural 

 selection, these developments, confined thus to the male sex, and 

 of no conceivable utility, are a puzzle to the rigid disciples of 

 Darwin. My own opinion * has long been that such develop- 

 ments (together with many others, peculiar to the male sex) aro 

 simply the results of the greater vital force or energy of the 

 male organization ; and are only kept in check by the hindrance 

 and positive evil that they may bring with them to their 

 possessors in the struggle for life. Of course, the operation of 

 natural selection will come in, through the advantage given to 

 individuals in which the vital force is the most powerful ; and 

 will thus indirectly tend to increase those developments which 

 are, primarily, the result of that forco. 



The Eyes 

 Are placed at the fore part of the caput, sometimes in front of 

 it, at other times on the upper surface ; often partly iu front and 

 partly above (see various figures in pis. i.-v.). They are simple, 

 immovable, six or eight in number in all the known British 

 species, though a few exotics possess no more than two or four. 



* In a oorrespondenoe, several yoars since, upon this point, Mr. Darwin 

 did not agroo with my views upon it. Very lately, however, I have had 

 the satisfaction of seeing those views stated and upheld by Mr. Alfred 

 Russell Wallace, in his recent moBt interesting work, " Tropioal Nature," 



