30 
THE VOYAGE OF H.M.S. CHALLENGER. 
and slender, and reaches the frontal margin ; the liagelluni is not covered by the rostral 
spines. The merus of the outer maxillipedes is distally truncated, with a rather 
prominent antero- external angle, and the next joint is articulated at the antero-internal 
angle of the merus. The chelipedes are moderately developed and spinuliferous, palm 
smooth, not turgid, fingers unarmed and acute, ambulatory legs moderately elongated, 
with the merus-joints, at least, spinuliferous ; dactyli nearly straight. 
But two species of the genus are known, the type Ergasticus clouei, A. Milne 
Edwards, dredged off Toulon in 445 (or 455) metres, and at the Cape Verde Islands in 
38 fathoms, (Studer) ; and Ergasticus naresii, described below. 
This genus is nearly allied to the following ( Echinoplax ), but the spines of the 
rostrum are armed only with one or two small accessory spinules near the base ; the 
post- abdomen (in the female specimen in the Challenger collection) is six, not seven- 
jointed, with the ultimate and penultimate joints coalescent, and the merus-joint of the 
outer maxillipedes is somewhat produced and rounded at its antero-external angle. 
The orbit also, on account of the spinules which surround it, is better defined than in 
most genera of Inachidse, to which group Ergasticus must, I think, be referred on account 
of the slenderness of the basal antennal joint. 
Ergasticus naresii , n. sp. (PL V. fig. 3). 
The carapace is scantily clothed with fine curled setae, and is everywhere closely 
and rather finely granulated, and bears several longer spines ; of these three are placed 
in a transverse series on the front of the gastric region, and one behind them, two on 
the cardiac region, two on the intestinal region, close to the posterior margin, and one 
or two on each branchial region ; the sides of the carapace and the posterior margin, 
also, are spinuliferous ; about five spines, including the strong postocular spine, 
define the upper margin of the orbit (of these one is bifid or trifid), also three or four 
spinules define its inferior margin ; the spines of the rostrum are slender, straight, and 
considerably less than half the length of the carapace ; beneath the base of each is a 
small spine, besides the median spine of the interantennulary septum. The eyes are 
moderately robust, setigerous. The very slender basal antennal joint bears several 
small spinules on its inferior and outer margin ; the merus and ischium-joints of the 
outer maxillipedes are granulated. The chelipedes (in the female) are about as long as 
the carapace and rostrum, very slender ; the spinules of their merus-joints increase in 
length toward the distal extremity of the joint ; carpus shorter than the palm ; palm 
about as long as fingers, very slender, not more dilated than the carpus, and spinu- 
liferous both on its inner and outer faces ; fingers slender, smooth, very minutely 
denticulated along their straight inner margins and with acute apices ; the ambulatory 
legs are granulated, spinuliferous and setose, with none of the joints compressed and 
