156 
THE VOYAGE OF H.M.S. CHALLENGER. 
In neither of the specimens I have seen is the front sub triangular as in the original 
description, which I think to be erroneous in this particular. 
The species is apparently well characterised by the uniformly granulated carapace, 
which is covered by a fuscous pubescence which arises in tufts of two or three setse, from 
each of the granules of the dorsal surface, and by the wide, denticulated or granulated 
teeth of the antero-lateral margins, as shown in the figure referred to. 
In the specimens I have examined the front is four-lobed ; the median lobes 
subtruncated and somewhat more prominent than the lateral lobes, which are small and 
dentiform, and situated just inside of the inner canthus of the orbit. 
Another specimen in the British Museum collection which was designated (though not 
by White), Pilumnus scabriusculus, certainly does not belong to this species, but to the 
variety of Pilumnus longicornis, described below, having a deeply incised four-lobed front, 
and prominent spiniform antero-lateral marginal teeth. 
The Challenger specimen, which is rather the larger, has the following dimensions : — 
Adult $. 
Lines. Millims. 
Length, of carapace, .... 
10£ 22 
Breadth of carapace, nearly 
13~ 27 
The pubescence of the carapace and limbs is yellow ; the merus-joints of the 
ambulatory legs are thin-edged and acute, but are not distinctly carinated as in the 
species designated Pilumnus dilatipes, Adams and White. 
Pilumnus normcmi , n. sp. (PL XIV. fig. 2). 
The carapace is broader than long, longitudinally convex, and covered with a short, 
thick, close pubescence, from amongst which spring numerous longer hairs. The front is 
but slightly deflexed, and is divided by a deep median sinus ; the median lobes are 
broad, subtruncated, and obscurely granulated on the margins, the lateral lobes very 
small and dentiform. The surface of the carapace, beneath the pubescence, is smooth, 
not granulated. The orbits are obscurely granulated on their upper margins, and more 
distinctly on the lower margins, where the granules tend to become spinuliform as they 
approach the inner subocular spine. The antero-lateral margins are armed with three 
strong, simple spines, behind the spine at the exterior angle of the orbit, which is 
smaller than the antero-lateral spines ; there are no spines on the subhepatic and 
pterygostomian regions, which are slightly pubescent, but one or two small granules 
on the subhepatic region. The basal antennal joint does not nearly reach the infero- 
lateral process of the front. The left chelipede is wanting, the right (in the male) is 
moderately robust ; merus-joint granulated on its upper and antero-inferior margins, and 
armed on the upper margin with a spine immediately behind the small distal spine ; 
