108 
Xk'IIOLLS — N~(^u' (rcnus aiuJ f^pcdrs of Ampliipods. 
; as a -wliole the appendage (in the female) is more 
slender than the lirst antenna of the male, -whereas in U. u'cstralis 
this doe^< not a])])oar to l>e the case (diilton, 192d, Figs. 2a ic 3a). 
In the ]ieraeoii the side plates are relatively short -with the 
inferior margin rounded and (dosely set with long setae which 
a])pear to l)e mueli more numerous than in U. wesfraUs. The lirat 
gnathoj)od of the female (PI. XII, Fig. 6) as compared with the 
second gnatho])o(l, has tlie earjuis considerably longer, l)ut not 
so distinctly widened distally, and the propod smaller. In the 
mal(‘ (PI. XIT, Fig. 3) the first gnathopod seems not to differ 
v(*ry markedly from that, of wedmUs. The second gnathopod 
of the f<'inal(' (PI. XII, Fig. d) agrees (juite closely -with that of 
r. n'csfi'dlis exce])i that th.’ besos of the former is relatively 
‘^liorter and stouter and the limb as a whole immensely more setose. 
V(‘ry large* marsupial plate, a large branchia and a small simple 
e.ccesseiy braiudn.-i are found related to the basal joint of this 
limit. !n the male (PI. XII, Fig. I) this appendage exhil)its a 
number of mimtr differences in the several joints from the corre* 
sjtonding’ structures in F. irrsfraUs, the meros of the appendage 
Iteiug relatively shorter and broader, the carpus much less evidentlv 
triangular in outline, the propod moi'e nearly oval, the dactyl 
longer and lutt so strongly curved. There is iio extension of the 
]ialniar edge beyond the tijt of the dactyl siudi as Chilton shows 
for I . ver.sd/'u/as-. Tlie outstanding difference, liowever, is due to 
the remarkable develojimeiit of long setae, arranged in bunches 
ii]»on tlie terminal joints. 
A largely deveh)])ed setosity is shown in some others of the 
freshwater Ani])]iipoda recoiaUui from Fasten) Australia, as in 
Atploidcn (fa'orii-'i and (himmanis (msimlis (Sayce 1901) but in 
none of tliese does it attain such an extreme development as in 
this W('Stern Austialiaii form. The sexual difference noted bv 
( hilton (192:)) in Use Hiit'd urojHid of U- 'U'Cfitro.Us is ecpially well 
marked in I . setosa (PI. XIH, Fig. 7-8) tlu* male alone l)earing 
upon the distal end of tlie outer ramus a combdike ]ilate with 12- 
Id stiff seta(‘. In its ])ro]Hudioiis, as compared with the third 
uiopod of I . (crtif raJis, the jH'dumde is, ])erhaps, slightly larger, 
and IS as liroad as long, wluu-eas in l\ iresfralis tlie breadth is 
miicli greater than the length; both rami being relatively shorter, 
i lie inner ramus is smaller generally, the outer less than twice 
ilie length of the peduncle, with the distal joint quite half the 
Imigth of tlie proximal. Tlie telsou (Id. Xlfl, Fig 9) is as broad 
a.i long and cleft scarcely jiiore than half its length, the two 
liortions hearing, sui)-a])icnl]y, two or three spines and several 
longer and nioi'o sk-nder setae, in Avhich arrangement it differs 
from tlie otlier sjiecics of this genus. 
