EPIDERMIS OF SPIDER." 67 



langia, or Harvestmen, which run always on the ground 

 amongst moss and leaves, and are of the lowest rank in the 

 society of Spiders, have but two eyes, seated on a tubercle or 

 watch-tower on their back. 



There are seventeen different positions at least in the eyes 

 of those Spiders most common to us. 



The jaws or chelifers of the Spider properly speaking 

 the mandibles are various in form, but always tremendous 

 weapons, not only from their size and sharpness and the 

 serrated edges and spines with which they are beset, but 

 also because the upper joint contains a little sac of intense 

 poison, which is emitted through a minute orifice in the 

 next joint, and effectually kills whatever insect is bitten. 



The palpi, or feelers, serve as organs of taste and touch, 

 and also as distinguishing marks of the sex. The male 

 Spider has very large knobbed palpi, by which it is easily 

 recognised. 



EPIDERMIS OF SPIDER. 



The skin of the Garden Spider (Epeira) is frequently 

 mounted, and displays very beautiful undulating lines, sur- 

 rounding the roots of the hairs. These concentric markings 

 arise from the existence of folds in the inner membrane, 

 beneath which lies a layer of pigment cells, to which the 

 variegated appearance and beautiful colours of the Arach- 

 nida are owing. 



The skin is merely washed, dried, and mounted in 

 Balsam. 



