266 A. D. MICHAEL ON A SPECIES OF GAMASUS. 



Colour — Yellow-brown, of medium depth, legs darker. 



Texture — Smooth, but not polished. 



Body — Form almost oblong, except the anterior margin of 

 the dorsal shield, which projects strongly in the centre, above 

 the oral tube, and has a very rounded outline in the projecting 

 portion. Dorsal shield separated from the ventral, and divided 

 in the centre by a transverse line, and slightly indented at that 

 place, showing the membranous margin. Oral tube, with upper 

 part (epistome) simply triangular (Fig. 4) with smooth edges. 

 Mandibles (Fig. 3) with the shaft (first joints) short ; the fixed 

 limbs of the chelae (second joints) short and tridentate, i.e., 

 with one bifid tooth at the end and one large single tooth ; the 

 movable limb (third joint) very long, five times as long as the 

 fixed limb ; almost straight, spear-like, sharp-pointed, with one 

 large tooth near the base, and a thin, sharp blade, deepest 

 posteriorly, running along the median line of the distal half, 

 and ending quite suddenly. There is a semi-circle of stiff 

 bristles just behind the articulation of this limb of the chela. 

 Some of the hairs on the palpi are pectinated (not strongly). 

 There are four fine, white hairs on the projecting portion of the 

 anterior edge of the dorsal plate, and numerous similar hairs 

 round the periphery, and on the dorsal plate. 



On the ventral surface the sternal plate is undivided, and the 

 ventral and anal plates are fused, but separate from the sternal 

 and dorsal plates. There is a chitinous arch over the genital 

 opening. 



Legs of moderate length ; the first pair (Fig. 6) thin and 

 straight ; joints of nearly equal thickness throughout. The 

 second joint (Fig. 11) has a great axe-blade-shaped chitinous 

 projection in the median line above. This leg terminates in a 

 membranous pad in which the shaft of the claws is sunk ; the 

 caruncle is very large and broad ; there are numerous fine hairs 

 on all the joints. The second leg (Fig. 7) is very greatly 

 thickened, but gradually diminished to a point. The first two 

 joints are very large, then there is a sudden constriction, then 

 the third joint is extremely thick, with a great rounded elbow ; 

 from this point the leg diminishes, ending in a strange, slightly 

 recurved, pointed portion, which bears a certain resemblance to 

 the form of the human foot ; from the under side of what 

 would be the heel proceeds the long-shaped caruncle and strong 



