486 ONISCIDiE. 



rounded margin and a concave upper surface. The seg- 

 ments of the bodj have the posterior angles acute. The 

 third, fourth, and fifth segments of the tail are largely- 

 developed, their lateral margins being continuous with 

 that of the sides of the body-segments. The terminal 

 segment of the tail is elongate-conic, and pointed at the 

 tip, with the upper surface slightly convex, and extending 

 to about one-third of the length of the outer division of 

 the terminal appendages of the tail, which are elongate, 

 slender, and pointed at the tip. The general colour is 

 iron-grey, with clear borders to the segments, and with a 

 row of ill-defined whitish spots on each side of the body, 

 parallel with the lateral margins. When alive, it rolls 

 itself into a perfect ball on being alarmed. 



Specimens taken near London (at Highgate ?) by Mr. 

 Francis Walker, are in the cabinet of the British Museum. 



