24 
W. M. TATTEESALL. 
Eyes (Figs. 1, 2 ancl 3) small, united at their base into a thick flattened pad, from 
the anterior part of which proceed two thin, short, sub-triangular, slightly-diverging 
lappets, which do not reach the middle of the basal joint of the antennular peduncle ; 
visual elements entirely absent. 
Antennular peduncle (Fig. 2) short and stout, its three joints sub-equal in length 
and quadrangular in outline ; basal joint, with a single long seta on its internal distal 
corner, and a more or less continuous submarginal row of setae across the anterior 
dorsal region ; second joint with about seven long stout plumose setae on its inner 
margin and two or three long setae on the outer distal corner ; third joint with about 
eleven long stout plumose setae on the inner margin. On the dorsal surface of the 
basal joint, partly concealed by the eye in dorsal view, is an organ of rather 
problematical function (Figs. 2, 4 and 5). It appears to consist of a shallow depression 
bounded by a raised ridge marked with pigment, and overhung by a membranous flap, 
which apparently rises from its posterior border. The flap only imperfectly covers the 
depression. In the preliminary notice of this collection it was suggested that this 
organ might prove to be auditory in function, but under moderately high powers of 
the microscope no otoliths or even sensory hairs could be distinguished in the 
shallow pit. 
Antennal peduncle longer than the antennular, and considerably more slender ; 
distal joint shorter than the preceding. 
Antennal scale (Fig. 2) lanceolate in shape, about three-and-a-half times as long as 
broad, apex evenly rounded, the whole of the inner margin and distal third of the 
outer margin setose; proximal two-thirds of the outer margin devoid of setae, but 
armed with eleven strong spines, the proximal one of which is the shortest, and is 
situated at the end of the proximal quarter of the outer margin, the spines increasing 
in size distally; spine on the outer distal corner of the basal joint short, but 
prominent. 
Mandibles (Fig. 6) with the cutting edge prominent and molar process well- 
developed and rather long; between the cutting edge and the molar process is a 
single spine-like seta, and in the left mandible a lacinia mobilis in addition; palp 
(Fig. 7) rather long and powerfully developed, terminal joint shorter than the 
penultimate, both joints armed on both outer and inner margin with numerous long 
and rather stout setae. 
First maxilla (Fig. 8) having the outer lobe much larger than the inner, and 
armed at its apex with about thirteen spines, behind which is a row of five plumose 
setae; inner lobe armed at its tip with four long plumose setae. 
Second maxilla (Fig. 9) consisting of the usual three lobes, a two-jointed palp 
and outer setiferous plate, the setae arming the appendage being numerous and 
rather strong. 
First thoracic limb (Fig. 10) short and stout, devoid of exopod, but with well- 
developed epipod; third joint small; fourth joint with numerous setae and a row of 
