1886.] DURING THE VOYAGE OF H.M.S. ‘CHALLENGER.’ 109 
female there are several shorter ones in addition. The first abdo- 
minal segment has a single row of comparatively short backwardly- 
directed spines ; on the second and third segments these spines get 
to be considerably longer, especially the lateral spine on either side, 
which marks the commencement of the abdominal shield. The 
abdominal shield in both sexes is covered with longish curved 
spines ; just above and near to the termination of its lateral margins 
are an extremely long pair of spines directed outwards and slightly 
upwards. ‘The proximal joints of the antenne and of the thoracic 
appendages are furnished with spines. The uropoda are tuberculate 
in the male and spiny in the female. 
Station 147 ; 1600 fathoms. 
5. ARCTURUS PURPUREUS, l. sp. 
This species is represented by a single female, which is of a 
purplish colour, It measures 18 millim., the length of the antennee 
is 31 millim. 
On the head between the eyes are a pair of long forwardly curved 
spines; the hinder portion of the head is occupied by a rounded 
median convexity; on the antero-lateral margin is a very short 
forwardly directed spine, beneath which the margin is excavated by a 
semicircular notch. Of the first four thoracic segments, the fourth 
is rather the shortest; each of the segments bears an outwardly 
directed spine on each side of the body, corresponding in position to 
those upon the head; close to the lateral margin of each segment 
and projecting over the epimeron is another long spine; the first 
segment differs from the succeeding in having no free epimera, and 
the lateral margin has two spines instead of one, of which the 
anterior is the longer; the fourth segment has also a second spine 
at its postero-lateral margin. Of the three posterior thoracic seg- 
ments the first is the largest; the epimera of all have a long out- 
wardly directed spine ; the first of these segments has in addition a 
tergal spine on either side exactly overlying the epimeral spine. The 
first abdominal segment has a pair of long lateral spines and a pair 
of short ventral spines; the third segment has a pair of lateral 
spines. The abdominal shield is oval, with a faintly marked central 
keel, terminating posteriorly in a long spine; its lateral margins are 
flattened and unite posteriorly ; on either side are two flattened 
spines situated at equidistant intervals. The antennz and anterior 
thoracic limbs have a few spines upon the proximal joints; the 
uropoda are granulated, but bear no spines. 
Station 23; 450 fathoms. 
6. ARCTURUS SPINIFRONS, 0. sp. 
This species reaches to a length of 13 millim., the antenne 
measuring 20 millim. The body is extremely tuberculate, but there 
are no spines except a single pair upon the head ; the lateral margin 
of the head, as in A. anna, is notched ventrally. The four anterior 
thoracic segments are subequal, each has a posterior ridge which 
