32 
THE VOYAGE OF H.M.S. CHALLENGER. 
separated by external characters of small importance, I should have preferred to regard 
it as a subgenus of that genus. It is also nearly related to Plistacantha, Miers, but is 
distinguished by the rostral spines, which are widely divergent from their base. But its 
nearest ally is apparently the preceding genus ( Ergasticus ), from which it is only distin- 
guished by the more numerous accessory spinules of the rostrum, the seven-jointed 
post-abdomen in the female, and the somewhat different form of the merus of the 
exterior maxillipedes. 
Echinoplax moseleyi, n. sp. (PL IV. fig. 2). 
The body and limbs are covered with very numerous, closely set, slender spinules, 
interspersed among which are some rather longer spines and fine hairs. The carapace is 
subpyriform, rather convex, longer than broad, with the depressions between the regions 
almost obliterated ; several spines are placed upon the upper orbital margin. The spines 
of the rostrum are slender, strongly divergent from their bases, nearly straight, acute, 
and more than half as long as the carapace ; they bear three or four strong spinules upon 
their exterior margins and inferior surface. The pterygostomian regions and the sternal 
surface at the base of the ambulatory legs are spinuliferous, but the epistoma is smooth 
except at its margins. The post-abdomen in the female is narrow*, with all its segments 
distinct and spinulose ; the spinules arranged in transverse series ; the terminal segment 
is distally rounded. The eye-peduncles are retractile and armed with one or two 
spinules ; two strong spinules are placed upon the interantennulary septum ; the basal 
joints of the antennules are spinuliferous, the basal joint of the antennae very slender, 
and armed with about four longer spinules, and the two following joints each with one 
or two smaller ones ; the ischium and merus-joints and the exognath of the outer 
maxillipedes are spinuliferous ; the ischium-joint has its antero-internal angle somew T hat 
produced and rounded ; the merus is truncated at its distal extremity, with the antero- 
internal angle scarcely at all emarginated. 
The left chelipede (in the female) is slender, and nearly as long as the carapace and 
rostrum together ; all the joints (except the dactyli) are spinuliferous, the spinules 
longest on the merus-joint, which is longer than the palm and fingers together ; the wrist 
is short ; palm very slender, not thicker than the wrist and less than twice its length ; 
fingers naked, slightly incurved, scarcely denticulated on their inner margins and distally 
acute. The ambulatory legs are very long and slender, those of the first pair about 
three times the length of the carapace to base of rostrum ; the joints all slender, the 
penultimate not more dilated than the others ; the dactyli straight ; the joints (except the 
dactyli) are armed with spinules and clothed with long hairs, the dactyli are hairy, but 
not spinuliferous. Colour (in spirit) light brownish-yellow. 
