ISOPODA. 59 
fourth shortest, subequal in length; the second and third also subequal, but little 
longer. All straight, the first partially enclosing the cephalosome. The three posterior 
segments subequal in length, increasing in curvature and decreasing in breadth to the 
last. Lateral margins of all the segments more or less truncated, the first three 
obliquely so, and all with distinct epimera, triangular in shape. 
Metasome, a single small segment wedged in the curvature of the preceding 
segment, and a urosome, large vaulted, fringed, but not thickly with spinous sete, and 
which form two small groups distally. Ventrally it forms a pocket for the pleopoda. 
In shape the urosome varies largely, in the smaller specimens it is ovoid with a slight 
depression for the reception of the diminutive uropoda. In the old adult males it 
becomes globular, with a truncated projection distally armed with two small groups 
of spines. . 
The males resemble the females, except that the latter are very much broader and 
the mesosome ovoid. 
First antenna, the short peduncle is two-jointed. The first joint is short and stout, 
the second is slender and a little longer; the multi-articulate flagellum is about half as 
long again as the peduncle. 
Second antenna, very long, peduncle six-jointed. The first three joints are very 
short, the second being as long as the other two together, and constricted in the 
middle ; the other three joints are long, the fourth is long, the fifth much shorter 
and armed distally with a spine; the sixth is simply enormous, longer than the two 
preceding together. It is very slender, and provided with sete throughout. The 
multi-articulate flagellum is longer than this joint. 
Mandible. Strong, curved, cutting edge with two long teeth anteriorly, a third 
with which is associated a group of spinous sete. Molar tubercle very prominent, 
its edge produced to a fine point posteriorly. Palp three-jointed, second joint a 
little the longest, the other two subequal ; the second joint has two, and the terminal 
one three or four stout setee armed with very fine closely set teeth. 
First maxilla. Normal, the inner lobe terminates in three spinous sete and a 
smaller one; these are coarsely plumose, at least on one side. External to these is a 
group of finer sete. The outer lobe has about ten stout pectinate spines distally, 
another row of them internally, a short distance below. A group of much finer 
ones occurs on the inner edge of the joint. 
Second maxilla. Normal, a rather broad blade reduced to about half its diameter 
in the distal half. This portion forms a blade, the inner and distal margin of which is 
thickly covered with stiff sete. The external joint is bifurcated, the inner part being 
the stouter, both terminate with four long setze. 
Maxilliped. A short basal joint, the masticatory lobe is two-jointed, subequal in 
length. The distal joint is rounded externally and armed at its extremity and 
internally with coarsely plumose sete. The inner margin carries four papilliform - 
teeth about the middle of its length. The palp is five-jointed, the first short, the 
P 2 
