REPORT ON THE ISOPODA. 155 



segment being somewhat hollowed for this purpose, The terminal segment of the 

 abdomen, including the telson, is a broad plate almost circular in outline ; the anterior 

 region, which represents the tergum of the sixth segment, is convex and marked off from 

 the flattened telson ; the latter has a faint median longitudinal carina which is grooved, 

 and there are also a pair of lateral carinse. 



The antennxdes (see fig. 3) are stout and swollen and consist of only two joints ; the 

 basal joint is almost spherical and very small, the distal joint is much longer and is 

 slightly curved upwards ; it terminates in a pointed extremity. 



The antennai have a more normal structure ; the peduncle consists of four joints ; of 

 these the two first are short and subequal, the third is very long, longer than the two 

 basal joints taken together, the fourth joint of the peduncle is also elongated but shorter 

 than the third ; the flagellum is nine-jointed. 



The mandibles are very powerful apj)endages ; the cutting-edge is chisel-like and 

 coloured of a dark brown ; there is a three-jointed palp. 



The maxillie of the first pair are not remarkable in their structure ; they are two- 

 lobed ; the cutting-edge is fringed with stout brown coloured spines. 



The maxillse of the second pair are two-lobed. 



The maxillipedes (see fig. 4) are remarkable on account of their very rudimentary 

 structure ; they appear to consist of only two joints ; the basal joint, which articulates with 

 the head, is elongated from side to side at its articulation, but narrower distally ; the distal 

 joint is smaller, and oval in form ; both appendages had the same structure, and I am 

 therefore inclined to think that it is all that is really represented in the species, and that 

 there is nothing defective in the specimen. 



The thoracic appendages increase in size up to the sixth pair ; I am unable to say 

 anything about the size of the seventh pair of limbs, as they were defective. 



The first pair of appendages are cheliform ; the basal joint is the longest and stoutest, 

 and is grooved on its inferior surface for the reception of the rest of the limb, which can 

 be folded back like the blade of a penknife ; the second, third, and fourth joints are very 

 short and decrease progressively in size ; the fifth joint is longer, and is oval and swollen ; 

 the sixth joint is a comparatively slender spine which can be bent back upon the penulti- 

 mate joint. 



In the second pair of appendages the third and fourth joints are proportionately 

 longer ; I am unable to say whether these appendages are chelate, as the distal joints of 

 the limb were missing. 



The remaining appendages are not chelate ; they differ from the first pair in the 

 greater length of the second, third, and fourth joints, in the extreme slenderness of the 

 fifth joint, and in the minute terminal claw which represents the sixth joint. The 

 basal joint of these appendages is longitudinally excavated as in the case of the first 

 pair. 



