158 
RECORDS OF THE AUSTRALIAN MUSEUM. 
posteriorly the setae are few or wanting. The spines are disposed 
as follows: three equally spaced in a median line, the first situated 
at the base of the rostrum, the second and third on the gastric 
region. There is a spine immediately posterior to each orbit, and 
another on each side, situated at a short distance inwards behind 
the latter and in a line with it and the antero-lateral angle of the 
carapace. There are five or six submedian pairs ; the first are 
seated on the gastric region and are rather widely separated, the 
remaining pairs are arranged in the form of a narrow V on the 
cardiac area, with a single median spine at their base ; a few 
occur on the branchial region in a line with the inner orbital 
prominence, and about ten form a transverse series at a short 
distance from the hinder margin of the carapace. 
Lateral margins of the carapace armed with fourteen or fifteen 
more or less compressed spines ; of these, five are in advance of 
the cervical incision, the anterior one is large and prominent, the 
succeeding four gradually diminish in size as the well-marked 
cervical groove is approached, the latter is bounded posteriorly by 
a spine equal to or larger than that at the antero-lateral angle, 
the eight following are subequal in size and in distance apart, 
their outer borders are beset with tubercles. An irregular sub- 
marginal series of spiniform tubercles is situated on the posterior 
half of the carapace immediately above the lateral margin; these 
form one or two rows and are most pronounced posteriorly. 
A sharply defined, deep, smoothish, transverse groove extends 
from side to side across the hinder part of the carapace, at a 
distance of about 7 mm. from the ciliated posterior margin ; 
laterally the groove is nearly twice as wide as at the centre. 
Pleon strongly sculptured, clothed with setiferous tubercles. The 
first segment is evenly convex above and below, and exhibits 
superiorly a well-marked transverse groove, situated much nearer 
the posterior than the concealed anterior margin, and it descends 
on each side to the coxal plate ; the latter is small and bilobed. 
The anterior lobe is broad, rounded, and its margin is continued 
inwards to the end of the transverse groove ; the posterior lobe is 
triangulate and acute, its point is directed outwards and down- 
wards ; the posterior margin is slightly crenate and oblique. 
The second to sixth segments bear raised arborescent markings ; 
all, except the last named, have a median carina. Each segment 
is transversely grooved and somewhat depressed anteriorly ; the 
groove is bounded by a raised crenated line, which is just visible 
on the first three, but cannot be seen on those succeeding without 
bending the pleon downwards. The inner process of each coxal 
plate is limited by a well defined smooth groove, which extends 
from the anterior depression to the articular condyle. 
The inferior surface of the second segment is much less curved 
than the first ; the convexity diminishes to the fifth, which is 
