60 
THE VOYAGE OF H.M.S. CHALLENGER. 
Naxia serpulifera, Milne Edwards, not uncommon on the Australian Coasts ; Naxia 
hirta, A. Milne Edwards, from the East African Coast and Mascarene Islands ; Naxia 
robillardi, Miers, from the Mauritius (30 fathoms) ; and the very distinct species described 
below as Naxia hystrix, which was dredged at Amboina in 100 fathoms. 
Naxia hystrix, n. sp. (PI. VI. fig. 4). 
The body is everywhere clothed with very close set knobbed hairs, interspersed among 
which are longer setae, which are most abundant upon the rostral spines ; the legs, also, 
are rather thinly clothed with a very short pubescence, and with some longer hairs placed 
at wide intervals along the margins of the joints. The carapace is subpyriform, longer 
than broad, moderately convex, and covered with long spines, disposed as follows : — three 
in a transverse series, and one (median and posterior) upon the gastric region, one (long) 
upon the cardiac, and one long on the intestinal region, one on each hepatic region, three 
(besides some smaller tubercles) on each branchial region, also three small spines on each 
lateral margin above the bases of the ambulatory legs. There is a strong spine on the 
upper margin of the orbit near the front, which bears a small subbasal, posterior, accessory 
tubercle ; behind this the upper orbital margin is widely and deeply emarginate, the notch 
with a median tooth or lobe ; the postocular lobe is rounded, little prominent ; the rostral 
spines are not half as long as the carapace, nearly straight, and divergent from their 
bases ; they bear a small accessory tooth or spine on their inner margins, not far from the 
distal extremity ; there is a spine at the antero-lateral angles of the buccal cavity, and a 
strong pterygostomian spine, also a strong spine on the sternum, between the bases of 
the chelipedes and first ambulatory legs ; the segments of the post-abdomen (in the 
female) are spiniferous, except the small terminal segment. The eyes have short 
peduncles and large rounded terminal cornese ; the basal antennal joints are longer 
than broad, and have a strong spine or tooth on the outer margin near to the base, 
and another at the antero-external angle ; the second and third joints are slender 
and visible from above at the sides of the rostral spines, the third rather longer 
than the second ; the outer maxillipedes are without spines on their outer surface ; 
the merus-joint is somewhat produced and rounded at its antero-external angle, 
and distally truncated. Chelipedes (in the female) very slender and slightly longer 
than the carapace and rostrum, the joints without spines, except a small spine 
at the distal extremity of the merus, which joint is nearly as long as the palm 
and fingers; the palm is not more thickened than the preceding joints, the fingers 
straight, acute, and closing along their inner margins. The ambulatory legs are very 
slender and decrease successively in length ; the first pair extremely long ; they 
are unarmed except for a small spine at the distal extremity of the merus-joints ; the 
