LOWER CARBONIFEROUS ROCKS OF ESKDALE AND LIDDESDALE. 81 
of socket. Antennules consist of two lengthened, apparently jointed propodites, 
each supporting a pair of filamentous whips, which are cylindrical near their 
base, and then become flattened and broadened somewhat before they taper 
rapidly at the tips. Antennz made up of jointed propodites with prodigiously 
large bidenticulated basal scales. Each propodite also supports a long cylin- 
drical many-ringed lash. The remaining cephalic appendages not distinctly 
observable. 
The walking legs, ten in number, are long and thin in their proportions, and 
somewhat flattened laterally. Their penultimate joints are even more so, and, 
as well, are strengthened by longitudinal flanges. The dactylopodites are sharp 
and spinose, and none of the limbs appear to be chelate. 
Abdomen long, and tapering backwards, composed of six segments, the 
last being the longest and much the narrowest. Their only ornament is a 
slightly thickened band along their anterior margins and a fold of the test along 
the median line of the sixth segment. They all possess triangular, pointed 
pleurz directed backwards. Those of the second segment overlap each way, 
the next three only overlapping those immediately in their rear. No appen- 
dages observable except on the sixth segment, which supports at each posterior 
angle a broad joint, to each of which are articulated a pair of expanded flaps. 
The strengthened part of the exopodite is much broader than in A.Parki. The 
telson is similar to that of A. Parki, but is narrower and more hastate. It also 
supports a pair of spine-like appendages on each side. 
Observations.—This species somewhat resembles A. Parki, but is easily dis_ 
tinguished from it by the general shape being much more elongated and 
tapering backwards, by the absence of the ridges on the carapace, by the long 
rostrum, by the sudden tapering of the body at the spring of the tail, by the 
telson, and by its possessing large basal scales to its antenne. 
Other points in the anatomy of this species can be made out from some of 
the specimens. The pedipalps of the maxillipedes were in all probability very 
long, and extended in front to near the tip of the basal scales of the antenne. 
The walking limbs seem all to have been simple, as in fig. 5a, ten limbs are 
accounted for, and none seems to be much more enlarged than the rest. They 
agree part for part with the hinder limbs of Nephrops Norvegicus, which they 
greatly resemble. In figs. 5a and 54 the coxopodites of five limbs on one side 
are observable attached to the thorax. Among the confusion produced by the 
crushing together of the gills and endophragmal system, exposed by the cara- 
pace being lifted in fig. 5a, one small fragment of the gill, apparently belonging 
to the fifth thoracic segment, is preserved. When magnified it shows a struc- 
ture like that of the gill of Palewmon, fig. 5e. 
The convexity of this species must have been considerable, for the indivi- 
duals are as often found on their sides as with their backs upwards. When 
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