4 
RECORDS OF THE AUSTRALIAN MUSEUM. 
In one large and evidently old male, about ^ inch in length, 
the second gnathopod was much elongated and at first sight ap- 
peared very different. A close comparison shows however that it 
is simply a more developed form of the gnathopod just described, 
and that the two are not dimorphic forms. The whole limb is 
much elongated and the setae are fewer and much smaller in pro- 
portion ; this loss of setae was also noticeable in the antennae and 
I have noticed examples in several other species which seem to 
show that it is a change that very generally accompanies age and 
increase of growth. 
The side-plates ( epimera ), (see fig. gn. 2 $ A) are small and 
are produced anteriorly into a moderately acute process which 
bears two or three setae ; the basos is of the same general shape 
as that found in the younger male but is much narrower, the 
ischios and meros are also similar but more elongated and the setae 
at the end of the meros are very few and small ; the carpus is 
immensely elongated and consequently much narrower in propor- 
tion, it is narrow towards the base and widens again distally, the 
anterior margin is quite free from setae except one or two very 
small ones at the apex, the posterior margin is straight with five 
distinct serrations, in each of which are two or three short setae ; 
the extremity is produced into two long processes about half as 
long as the propodos, the process formed of the postero-distal corner 
1 laving the sides parallel and the end truncate, the other, corres- 
ponding to the small rounded lobe in the younger male, with the 
outer margin straight, inner margin slightly concave, extremity 
rounded, quite free from sette ; the propodos is very long and 
narrow, the breadth not more than one-fifth the total length, the 
whole joint is much curved inwards, the inner margin being very 
concave and fringed with a row of scattered set?e ; the finger is 
stouter and blunter than in the younger male and has the inner 
margin smooth. The propodos is not movable quite in the same 
plane as that of the carpus, but bends back on one side of it so 
as to lie obliquely along its surface. 
I have seen only one very large male with the second gnathopoda 
like that shown in fig. gn. 2$ A. Most of them were more like 
the one represented in tig. gn. 2 $ B, but in some the two pro- 
cesses at the end of the carpus were a little more developed, in 
others a little less developed than those shown in this figure. 
Forms younger still than that represented in fig. gn. 2 $B would 
no doubt approximate more closely to the female in the form of 
second gnathopoda. 
The first pereiopoda agree closely with the description given by 
Stebbing, but T have not observed the “long transverse slit ” 
across the surface of the basos that he mentions. 
The second pereiopoda also closely resemble Stebbing’s descrip- 
tion. In both this and the preceding pair the side plates are 
