TUBICOLUS AMPHIPOD — CHILTON. 5 



produced antei'iorly 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 setaj. 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. S ^ and p7-p. 3 ? . The other 

 joints of the limb are practically identical in the two sexes and 

 agree closely with Stebbing's description. 



The fourth ^jereiopoda 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, 



