402 



MR. A. D. MICHAEL ON 



hairs instead of one pair, as in M. musculinus. These hairs are 

 nearly as long as the wliole length of the body ; both pairs curve 

 upwards at first, and then run backward and outward ; but the 

 pair near the centre are much the straighter. There are two 

 other much smaller hairs springing from each of the square pro- 

 jections. There are two large hairs on each side of tbe body, one 

 a little in front of, and one a little behind, the constriction between 

 cephalothorax and abdomen ; the hinder is considerably the larger. 

 There is a pair of large hairs on the dorsum of the cephalothorax, 

 and several smaller pairs on that of the abdomen. The claws of 

 the first two pairs of legs are extremely long, very slightly curved, 

 and rod-like. The legs of the fourth pair, although of the same 

 general form as in M. musculinus, are very much smaller in pro- 

 portion, they do not project behind the body, and are scarcely 

 tbicker than those of the first and second pairs ; they are much 

 shorter and narrower than those of the third pair, which extend 

 considerably further back than the body. Each tarsus of the 

 fourth pair bears a long flexible hair and a short stout spike still 

 nearer to the tip. On the inside of the flattened claw of each 

 third leg, at the proximal end of the claw, is a curved chitinous 

 process projecting inward, and a similar process is found on tbe 

 preceding joint. There are several pairs of long bairs on the 

 ventral surface, and a pair of stout spines behind the penis. 



The Female. — The female differs from M. musculinus more 

 than the male does. The abdomen of the present species is almost 

 cylindrical, although somewhat flattened dorso-ventrally ; it is 

 slightly smaller at tbe ends than in the middle, but is without 

 the bighly flattened form and the lateral angular projections found 

 in the other species. The wbole abdomen is covered by strong, 

 slightly irregular transverse wrinkles or ridges ; these are slightly 

 rough, but are not set with the well-marked and regular points 

 found on tbose of the female of M. musculinus. The length of 

 the abdomen varies greatly in different specimens, or more pro- 

 bably in the same specimens at diff'erent times : there is usually 

 one egg matured at a time, and as it is very long, it probably 

 elongates the extensile abdomen as it grows, and other circum- 

 stances will probably produce temporary variations in the length 

 of the abdomen. The variation in the length of the female noticed 

 in the measurements arises almost entirely from the abdomen. 

 The creature usually holds the hair of the mouse with the third 

 and fourth claws, and keeps the rostrum sharply inclined down- 



