1886.] DURING THE VOYAGE OF H.M.S. ‘CHALLENGER.’ 111 
8. ARCTURUS GLACIALIS, n. sp. 
This new species comes near to the last, but may readily be 
distinguished by the fact that the spines are more numerous, 
shorter, and more slender. The single example, a female, measures 
32 millim. The dorsal surface is densely covered with short slender 
spines, which extend on to the thoracic appendages and uropoda; 
the spines are of uniform length. The anterior margin of the head 
is excavated by a shallow semicircular notch ; between and in front 
of the eyes are a pair of long spines, inclined somewhat away from 
each other ; the spines on the thoracic segments are disposed in the 
following way :—each of the first four segments has a posterior and 
anterior ridge as in other species; both these are covered with 
spines, as are also the epimera; between the two ridges in all but 
the first segment are a pair of short spines; each of the three 
posterior thoracic segments is ridged, the ridge being beset with 
spines except in the median dorsal line. The abdominal shield is 
beset with spines, except in the dorsal median line, where it is 
grooved longitudinally. 
Station 153; 1675 fathoms. 
9. ARCTURUS ABYSSICOLA, 0. Sp. 
This species was obtained from two stations in the Pacific Ocean, 
but near to each other. 
The length is about 20 millim., the length of the antenne 42 
millim. Of the first four thoracic segments the second and third 
are equal in size and rather longer than the first and fourth; each 
of these segments is ridged posteriorly as in other species ; laterally 
the tergum is produced into a short tubercle and there is a similar 
tubercle upon the epimera; on the first segment this tubercle is 
prolonged into a spine ; on the inferior surface of the fifth segment 
is a short median transverse ridge ; the first abdominal segment has 
a pair of ventral tubercles ; the abdominal shield is keeled and 
terminates in a blunt spine, it is covered with a few low scattered 
tubercles. The anterior thoracic appendages are furnished with one 
or two spines upon the proximal joints; as in 4. anna the posterior 
thoracic appendages have not these spines. 
Station 184; 1400 fathoms. Station 281 ; 2385 fathoms. 
10. ARCTURUS STUDERI, N. sp. 
The extreme length of this species is 28 millim., length of antenne 
30 millim. The head has two pairs of long spines situated one 
behind the other, behind these again is a ridge bearing a few short 
spines ; the antero-lateral region of the head is notched ventrally 
as in A. purpureus, &c. The four anterior thoracic segments are 
subequal ; on the posterior ridge of the first Segment are a pair of 
minute tubercles on either side of the median dorsal line; laterally 
are two long spines equidistant from each other and the dorsal 
tubercles ; the lateral margin of the tergum is prolonged into two 
outwardly directed spinous processes ; in front of the posterior ridge 
are four minute tubercles arranged transversely ; the second segment 
