12 
T. Y. HODGSON. 
generally lias a very obvious depression in the centre. The next, or fifth segment, is 
the longest, and there is a progressive increase in length from the first to the fifth, 
this one bears more or less distinct traces of a median longitudinal division. The 
sixth segment is a little shorter than the preceding, and posteriorly it terminates in 
three lobes, the median is short and the width of the abdomen, the lateral ones are 
large and project along the sides of that structure. The last segment of the mesosome 
is much reduced in size and almost fills the interval between these lobes. Laterallv 
«/ 
the second and third segments of the mesosome are covered with small spines or 
tubercles, a feature which is not brought out in the figure in the ‘ Southern Cross ’ 
Report. The cephalon and every segment of the thorax bears laterally a number of 
long slender setae. A feature which is not alluded to in the original description is 
the crustaceous character of the exoskeleton, this is usually very prominent down to 
and including the fifth thoracic segment, although it is to a certain extent covered by 
a mass of diatomaceous matter. The posterior segments of the thorax and the 
abdomen are almost invariably thickly covered with a similar growth, often so much 
as to completely conceal all structural details. 
The metasome consists of six joints of subequal size, the telson, a pointed 
triangular structure with a few long setae distally being fused with the last one. The 
epimera are broad blades, curved to a slight extent backwards. The last abdominal 
segment has no epimera. The uropoda are well developed, the basal joint is short 
and stout, the two rami are subequal in length, but the endopodite is considerably 
broader than the exopodite, both are fringed distally with long setae and have three 
shorter ones on their external borders. 
The first antenna consists of a three-jointed peduncle and a short, four-jointed 
flagellum. The first two joints of the peduncle are short and subequal, the third is 
longer than the other two together, all bear a few setae distally. 
The second antenna comprises a peduncle of four joints and a flagellum of six 
or thereabouts. The first two joints of the peduncle are short, the third is about as 
long as the two preceding ones together, and the fourth is still longer; this one 
carries along the side of it a series of setae of increasing length. 
The mandible is scythe-like in general appearance, the amount of curvature of 
the free end being variable, the outer margin carries a sharp spur near its middle, and 
the inner cutting edge is slightly sinuous. 
The maxilliped is a small structure, the basal plate is rather large, comparatively 
roughly triangular and attached by its truncated apex. The masticatory process is a 
small clavate process bearing two stout knobbed processes on the inner side. The 
palp consists of four small rounded joints which taper slightly from the first, and each 
carries a few long setae on the outer margin. 
The gnathopod is a large pyriform spoon-like structure forming an operculum 
over the residuum of the mouth organs. It is attached on one side near the base 
and its rounded free margin is fringed with delicately plumose setae. Its surface is 
