REPORT ON THE CRUSTACEA. MACRURA. 791 



there is developed a broad and slightly curved plate, the concave surface of which looks 

 upwards, the margin being tufted with a thick mat of hairs ; the basis is shorter than 

 the ischium and like it has a flattened process, also tufted with hairs. These two processes 

 form a point of support for the distal joints of the long appendage when reflexed and at 

 rest. The limb being bent at the mero-carpal articulation, the lengths of the proximal 

 and distal joints are equalised so that the chela when so bent reaches the mouth and is 

 enabled to supply it with food. The coxa is short and robust. 



The second pair of pereiopoda is extremely long and forms the distinguishing feature 

 of this genus ; it is about one-third longer than the entire animal, so that a specimen 

 that measures 130 millimetres from the orbit to the extremity of the telson carries a 

 pair of these limbs nearly 200 milbmetres long. The coxa and basis are short, the 

 ischium is longer and slightly compressed horizontally ; the meros is twice the length of 

 the ischium and subequal with that of the carpos ; the propodos is twice and a half as 

 long as the carpos, and the palm once and a half longer than the carpos ; the pollex 

 is subequal to the dactylos, cylindrical, and but very slightly larger in diameter than the 

 distal extremity of the carpos, it is curved downwards in gradual continuation of the 

 lower margin of the palm, and is armed on the inner surface near the base with two 

 tubercles situated near together, the anterior being the larger and directed obliquely 

 backwards. 



The dactylos is long and slender, resembling the pollex, being slightly curved to 

 correspond and lie parallel with it, it is armed on the inner surface about one-third from the 

 articulation with a large flattened conical cusp, which with those on the pollex prevent 

 the fingers from impinging close together, whereas the apices of the two pass each other 

 when the chela is closed. The entire limb is finely granulated except on the dactylos and 

 pollex, where the granulations are coarser and more pointed, and on the under surface of 

 the propodos and carpos, where there are a few small tubercles. 



The posterior three pairs of pereiopoda are short, subequal, furnished with hairs, and 

 terminate in an unguiculate dactylos. 



The pleopoda are biramose and subfoliaceous ; the first pair has the inner branch pointed 

 and half the length of the outer, all the others are subequal ; the posterior pair helps to 

 form the rhipidura, the outer branch of which is longer than the inner, and is divided by 

 a diseresis, that is protected on the outer margin by a point that lies close against the 

 distal portion of the plate. 



The telson is one-third shorter than the outer ramus of the rhipidura and gradually 

 tapers to an obtuse point ; the dorsal surface is smooth and rounded, the distal half being 

 dorso-laterally furnished with two equidistant solitary short spines, and the extremity 

 is fringed on the under surface with a row of short stiff hairs, and at the outer angles on 

 each side with a long and short spine. 



