238 HISTORY OP BRITISH CRUSTACEA. 



domen fill up the notch between the two last rings, and do 

 not extend beyond the edge. When touched, they have the 

 power of rolling themselves into a ball. 



Gen. 121. ARM ADILLO, Latr. 



Latreille gave this name to these creatures from their 

 habit, when disturbed or alarmed, of rolling themselves into 

 a ball, like the curious, jointed, mailed mammalia of South 

 America commonly so called. In some places they are 

 called " pill-beetles," the former part of the name derived 

 from their appearance when rolled up being that of a pill. 

 The last false feet have the basilar joint very large, and almost 

 entirely filling up the notch between the fifth and sixth seg- 

 ment of abdomen. The body is highly convex above, and 

 very blunt at both extremities. The outer antennas are seven- 

 jointed, inserted in a hollow of the front ; the lateral caudal 

 appendages do not project ; the apical joint triangular. 



Armadillo vulgaris. Till Beetle. — Body smooth, of a 

 greyish-brown hue, with the hind margin of the rings of a 

 yellowish hue. 



Not uncommon in different parts of the country. 



The next sub-order of the Isopoda contains those species 

 which can swim; the abdomen ends in a large fin, furnished, 



