8 Mr. C. Cliilton on a new Species of 



is produced forwards and downwards to form the groove, so 

 that wlien the end of the limb is bent back upon the ischios 

 it is protected and held in its place both on the inside and the 

 outside. The meros is flat or liollow above and expands a 

 little distally, its articulation with the ischios is concealed in 

 a view from the outer side bj the prolongation of the outer 

 portion of the ischios. Tlie carpus is nearly as wide at the 

 base as the preceding joint, but expands distally and has the 

 end shaped something like a mallet, being produced both 

 above and below, the lower portion finely crenate — the exact 

 form will be learnt from the figure more easily than from any 

 verbal description. The propodos is attached to the upper 

 distal corner of the carpus ; it is nearly circular in shape, and 

 bears a small dactylos whifh ends in two claws as in the other 

 legs. The wliole limb is, in fully developed males, quite free 

 from setae ; the ischios and meros are rather thick through 

 from side to side, but the carpus and propodos are thinner and 

 plate-like. 



The whole leg is most striking in appearance and quite 

 unlike anything else that I liave seen among the Isopoda. 

 It most probably forms a grasping-organ of some kind, though 

 it is not easy to see exactly how it is used, and while grasping- 

 organs are usually formed by means of the terminal joints 

 (propodos and dactylos) in other species, in this case these are 

 small and more or less rudimentary. 



In young males the first pair of limbs is much more like 

 those of the female and quite differeut from those of the fully 

 developed male. One stage in the development is shown in 

 figure 8 h of Plate II. The basos is of fair size, though not 

 so long in proportion to the other joints as in the female ; the 

 ischios is much larger and already shows signs of its future 

 great expansion ; the remainder of the limb is practically 

 the same as in the female, except that there are fewer spini- 

 form setai on the carpus. A more advanced stage is shown 

 in figure 8 c of Plate J I. The ischios is moi-e enlarged, the 

 meros more elongated and more like that of the adult male, 

 the carpus has begun to take its peculiar mallet shape, the 

 propodos is becoming more rounded, and thesetaj have almost 

 disa])peared from the wliole limb. 



It will thus be seen that in this species, as in man}- other 

 cases, the young male rcsombks the female, and that tlie 

 peculiar characters of the adult male are acquired by a gradual 

 development *. 



* Sf(. I^iuwin'.s ' l)osifii( of Mail," p. :?.'^l' (stcriui idition). 



