Falco7ier : Abnormality in Spiders. 231 



periotl. In the first a wound never heals, but in the two others 

 persists only until the next moult, when the injury is not only 

 repaired, but all indications of the occurrence are obliterated. 

 In the intermediate stages the incident of moulting necessitates 

 the possession by the organism of a living formative dermis 

 capable of secreting a successive number of dead protective 

 epidermic investments, but in the perfect form the latter once 

 formed are permanent and cannot be replaced. This would lead 

 us to infer that the marks on the abdomen of spiders are not 

 the indelible records of accidents which have maimed the body, 

 but not destroyed the life, and that they should rather be 

 ascribed to faulty development. A spider can, however, 

 replace a lost limb. Individuals may sometimes be seen with 

 one leg of a pair shorter than the other. The short one is a 

 limb in process of renewal. This is in accordance with a 

 beneficent provision of Nature, not unparalleled in other forms 

 of animal life, but by different methods, whereby the creature 

 when seized by the leg is able to throw it off, and escape from 

 its assailant, preserving its life at the cost of a temporary 

 inconvenience. In one or two instances amongst the ' wolf ' 

 spiders, which have come under my notice, the reproduced 

 limb (at least I have taken it to be this one) has grown con- 

 siderably beyond the original length, as if the regenerative force 

 expended had been more than sufficient to effect the needful 

 restoration. 



With the exception of the last-named, the abnormalities 

 we have so far discussed are permanent. Others are merely 

 temporary and mainly associated with the period of moulting. 

 They may nevertheless, puzzle anyone unacquainted with them. 

 Such are the possession of a double set of eyes, the old in process 

 of peeling off the new ; the reticulated abdomen of Hilaira 

 uncata Camb., and H. excisa Camb., and the very thickly 

 dotted one of Pholcomma gibbiim Westr. Newly moulted 

 specimens are pale in colour, but gradually assume the deeper 

 tints proper to them, and as a rule deviate very little from 

 them, the colour of the body and limbs being often a good 

 discriminatory character between species closely allied. In 

 one strange-looking example of Gonyglidium mflpes Sund., a 

 female, wliich was sent to me from the north of Yorkshire, the 

 whole of the dark pigment of the various parts seemed to have 

 become concentrated on the caput, leaving the rest of the body 

 pale and unicolorous, and imparting to the creature a striking 



1910 June I. 



