28 Transactions of the Society. 



the cavity of which (camerostrum) it can be almost entirely with- 

 drawn, or from which it can be protruded to a considerable extent. 

 When fully exserted, it is nearly one-sixth of the entire length of 

 the creature, and is bluntly pointed, narrow, but gradually and 

 slightly widened until near the posterior margin, where it is 

 sharply constricted, so as to give the appearance of a neck. There 

 is a pair of fine, nearly straight rostral-hairs. The palpi show 

 from the dorsal aspect projecting beyond the rostrum ; the chelate 

 mandibles, which are large, also shov^ from the dorsal aspect ; 

 they are short and wide ; each limb of the chela is tridentate, two 

 of the teeth of the movable limb being close together like one 

 bifid tooth ; there is also a very small inner tooth near the distal 

 end of the fixed limb. The mandibles are ordinarily protruded 

 alternately. There is a well-marked transverse line dividing the 

 rostrum from the remainder of the cephalothorax, which part 

 widens gradually until near its posterior margin, and in its widest 

 part is almost as broad as the abdomen; its lateral margin is 

 slightly curved and very shghtly undulated. There is a sharp and 

 strongly-marked constriction where the cephalothorax abuts on the 

 anterior margin of the abdomen, and this constriction extends 

 right across the dorsal surface. There is a curved, fine hau' of 

 moderate length, a little in front of the postero-lateral angle. The 

 sternal surface shows an indentation between the first and second 

 pairs of legs. There is a short, longitudinal, chitinous sternum 

 extending from near the rostrum about one-third of the length of 

 the cephalothorax ; it is joined anteriorly by the epimera of the 

 first pair of legs, each of which is a single curved, chitinous blade, 

 arising from the anterior part of the insertion of the coxa. The 

 epimera of the second legs are similar in shape, but longer and 

 more curved ; they do not reach the median line, and are not joined 

 to the sternum. 



Legs short. The front pair scarcely passing the tip of the 

 rostrum, the hind pair not nearly reaching the posterior margin ; 

 all somewhat curved inward. The first pair inserted close behind 

 the rostrum, the second near to them, the two hind pairs are 

 abdominal, placed near together, but far from the two front pairs. 

 Coxae large and rounded, other joints gradually diminishing in 

 thickness to the distal end. Joints of nearly equal length ; tarsi 

 blunt, terminated by a short, stout, single claw, which can be almost 

 withdrawn between two membranous flaps, projecting one from 

 each side of the tarsus; there is also a short caruncle above 

 the claw. There is a long, flexible, tactile hair arising from each 

 tibia, several fine hairs on the tarsi, and a pair of short, straight 

 hairs on each of the other joints except the coxae. There is a 

 strange transparent, chitinous rod, on each tarsus of the first two 

 pairs of legs ; it arises from the proximal extremity of the joint, and 



