224 Proceedings of the Royal Society of Victoria. 



wards in an even curve to the inner distal margin. Inner 

 margin almost straight. Outer margin fringed with setae, those 

 at the distal extremity being plumose. The inner margin is 

 unclothed in this pair, but is thickly fringed with setae in each 

 of the others. The endopodite is as long as the exopodite, but 

 narrower, and except for two or three plumose setae at the 

 extremity is unclothed. The second pair is of the same shape as 

 the first pair, except that the inner margin near the end is 

 excavated to receive a small triangular secondary joint, which is 

 narrowly articulated close to the inner margin, and hangs only 

 a very little below the extremity of the primary joint. The 

 endopodite is broader than the first pair, and the " penial fila- 

 ment," which is borne by this joint, is short, elbowed at the base, 

 and pointing upwards. The third pair is of similar length to the 

 second, but the exopodite and epipodite are each broader, and 

 the protopodite has a long, narrow-ovoid lobe (epipodite) jointed 

 to its outer face. The structure of this lobe is thicker than the 

 exopodite and very vesicular, being similar to the endopodite 

 except that margin is fringed with long simple setae set some 

 distance apart. The fourth and fifth pairs agree in all respects 

 with the third, except in size, the fourth being a little shorter 

 and the fifth much shorter, so much so as to be almost as broad 

 as long, and the hind margin forming a full half circle. 



DESCRIPTION OF PLATES. 



A. — Hypsimetopus intrusor — Side view of the whole animal, a 



male of 15"5 mm. 

 B. — Cephalon and adjacent parts except buccal mass. 

 C. — Extremity of body with uropod attached. 

 Lfc. — Anterior lip. 



M^ and M^ — Right and left mandibles. 

 L'^ — Posterior lip. 



Mx^ and Mx^ — First and second maxilla. 

 M. P. — Maxillipedes. 

 Pr, 1, 2, 4, 7. — Pereiopods, numbered respectively. 



