158 THE GENUS PERIPATUS. 



While the colour of the ventral surface is practically the 

 same in all individuals, that of the dorsal diflfers in almost all. 

 The differences are due to the varying proportions in which 

 the green and brown pigments are present. 



To facilitate matters I will describe two extreme cases : (1) 

 a very dark green specimen (fig. 1), in which the brown is 

 very inconspicuous, and (2) a red specimen, in which the brown 

 predominates. 



(1) The skin between the close-set papillae, so far as it can be 

 observed, is a bluish grey ; but on the papillae the pigment has 

 a very dark green colour, except on a few, in which it is 

 brown (even these may be absent). The ground colour, i.e. 

 the colour of the skin between the papillae, varies in shade 

 in different places. On the dorsal sides of the legs and along 

 a dorso-lateral band at the bases of the legs, extending the 

 whole length of the body, it is lighter than elsewhere, while 

 on each side of the median dorsal white line it is much darker 

 than elsewhere. These differences may be partly due to the 

 closer aggregation of the papillae in one place than in the other. 



(2) The pigment of the skin and of most of the papillae 

 is a reddish brown, except on each side of the dorsal white line 

 and on the dorsal sides of the legs where it is green. Scattered 

 amongst the brown papillae are a considerable number of green. 

 The brown colour is of a lighter shade along a dorso-lateral 

 band, extending the whole length of the body at the base of the 

 legs, and from this band green papillae are almost entirely absent. 

 The brown pigment is, however, almost entirely absent from 

 the dorsal side of the legs on each side of the dorsal white line. 



The conditions intermediate between these two extreme cases 

 are due to the variations in the number of the brown papillae. 

 As a peculiarity of these intermediate cases may be men- 

 tioned the fact that the brown pigment extends into the skin 

 round the base of the brown papillae, giving the brown 

 papillae a brown setting, so that when a number of them occur 

 together the skin between the papillae has an entirely brown 

 colour (as in the brown specimens). Brown papillae are most 

 numerous in the light band at the bases of the legs, and are 



