TTJBICOLTJS AMPHIPOD— CHILTON. 
5 
produced anteriorly into a small rounded lobe tipped with setae, 
that of the first pair being considerably larger than that of the 
second. 
The third pereiopoda have the side plates very large, delicate and 
membranaceous. Those of the female are very much larger than 
those of the male, a fact which tends to confirm Mr. Stebbing’s 
supposition that they fulfil the function of marsupial plates. The 
side plates extend along the whole segment forming a small lobe 
in the rear and are of about uniform depth, the two lower corners 
being broadly rounded, the lower margin being usually slightly 
concave in the middle. The margin is somewhat uneven, entire 
or irregularly crenate, and is irregularly fringed with setae. The 
rest of the limb is attached to the side plate at the rear and 
usually projects directly backwards. The relative sizes of the side 
plates as compared with the rest of the limb in the two sexes can 
be seen by comparing figures prp. 3 $ and prp, 3 ? . The other 
joints of the limb are practically identical in the two sexes and 
agree closely with Stebbing’s description. 
The fourth pereiopoda have the branchial vesicles very small, 
narrow and bent at the base. The whole limb is much as described 
by Stebbing, but is usually provided with fewer seta? ; the lower 
margin of the side plates is thickly fringed with cilia in the male, 
but these are very delicate and I have failed to find them in some 
other specimens. 
The fifth pereiopoda and the pleopoda agree with Stebbing’s 
description and do not call for special remark. 
The uropoda which are represented in the figure as seen from 
above, agree with Stebbing’s description, the third pair however 
being very much broader in proportion to the length than the 
second pair. (See fig, ur. 1 &c.) 
The telson when seen from above proves to be bi-lobed as in 
Cerapus sismithi , the dividing cleft extending about half way 
towards the base, each lobe rounded and bearing on the surface 
two rows of sharp upturned teeth. 
Locality. — Port Jackson, New South Wales. 
Remarks . — The whole integument of the hinder portion of the 
body with the appendages is very thin and delicate, membranace- 
ous. The animal rests in the tube with the head and first segment 
of the pereion and usually the ends of the second gnathopoda pro- 
jecting out at the end (see fig. A) and the pleon is bent back upon 
the body as shown in figure B. Doubtless the sharp teeth, setae, 
and serrations on the uropoda and the telson enable the animal 
to fix this portion of the body to the inner surface of the tube, 
