of the Mole-cricket. 411 



tain particles of the excavated earth ; which, by filling up the 

 indentations of the claws, would necessarily impede their due 

 action. To obviate this inconvenience, an exceedingly curious 

 instrument is attached to the upper part of the concave sur- 

 face of this member : this instrument consists of two claws, 

 closely resembling those already described, having by their 

 side a small brush as it were, which terminates in two spines. 

 These two claws, together with the piece bearing the spines, 

 arise from a single piece, or handle, which is articulated in 

 such a manner as to move in a plane parallel to that in which 

 the four claws are placed, but in a direction opposite to that 

 m which they are moved : they are also placed in such a man- 

 ner that their points and cutting edges are opposed to the 

 points and cutting edges of the true claws ; and hence the two 

 parts, thus opposed to each other, act like the blades of a pair 

 of shears. When first I considered this mechanism, and re- 

 membered that in the localities where I had found the animal 

 the earth was frequendy traversed by fibrous vegetable roots, 

 which must necessarily retard its progress, I supposed that it 

 used this instrument as a pair of shears to cut through those 

 fibres. It is Rcisel's opinion, however, that the instrument is 

 intended to clear the true claws of the dirt that may from time 

 to time collect upon and clog them ; and unless both opinions 

 be true, Rosel's appears the more probable.— But I have not 

 yet concluded the account of the curious mechanism of this 

 member : for the brush which has just been described, has 

 only such an extent of motion as enables it to clear the two 

 uppermost claws, or at most the three uppermost; the two 

 lowermost however may effectually be cleared by a kind of 

 feathered spur, which, arising from the further extremity of 

 the jomt answering to the femur, proceeds directly towards 

 the lowest part of the burrowing instrument, and is easily 

 made to sweep over the surface of the two last claws by bend- 

 ing the intermediate joint, the only difference in its mode of 

 action being that it passes over their inner instead of their 

 outer surface. 



The middle pair of legs, which is the smallest of the three 

 pan-s, arises from the under part of the first segment of the 

 abdominal division : they pass out from the body at right an- 

 gles to the abdomen, and usually are seen in that direction 

 whether the animal be in motion or at rest. They consist 

 each of four parts ; a very short coxa, a femur and tibia 

 nearly equal in length to each other, and a tarsus which 

 consists of two long and an intermediate short joint, the last 

 joint terminated by two curved spines. "Inhere are several 

 sharp, hai d, straiglit s])inc^ near the ;inglc made by the union 



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