150 lilCHARD EVANS. 



much lighter in tint and warmer in tone than either the 

 median line and its lozenge-shaped areas or the flanks of the 

 animal. The sides of the animal agree in tint with the median 

 dorsal line, but become somewhat lighter in the immediate 

 neighbourhood of the walking appendages. The ventral 

 surface is grey in colour, but with a pinkish constituent in 

 some individuals. The spots corresponding to the ventral 

 organs, and situated mid-ventrally between the appendages, 

 are always a lighter grey. In the majority of cases the 

 antenna) are somewhat darker than the dorsal surface. The 

 darker and lighter areas on the dorsal aspect are produced 

 by a corresponding diiference in the colour of the papillae, 

 Avhicli are dark brown in one case and light brown in the 

 other. 



The Skin, with its Ridges and Papillae. — The skin is 

 thrown into folds or ridges, on which the papillc\3, both 

 primary and accessory, are situated. In the mid-region of 

 the body there are about twelve folds to every pair of 

 appendages. As a rule, seven of these pass uninterruptedly 

 from the mid-dorsal line over the sides and between the 

 appendages to the ventral surface. Of the remaining folds, 

 at least two terminate about halfway between the mid-dorsal 

 line and the legs, while the other three reach the appendages 

 and there end. The continuity of the folds is broken at the 

 mid-dorsal position by a very narroAv and clear line, Svliich is 

 visible only with the microscope. On either side of the line 

 in question, in the spaces between the folds, the openings of 

 the trachcic are situated. 



On the dorsal aspect of the head the papilhc present a 

 diffused arrangement. Around the base of each antenna 

 they arc arranged in three or four more or less complete 

 rings, on one of which the eye is situated. 'J'he rings in 

 question pass between the antenna), and those on either side 

 are not separated by a row of papilla) passing from the area 

 on top of the head, on Avhich the papilhe are irregularly 

 arranged, to a similar area situated on the ventral surface in 

 front of the mouth. 



