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R. S. BAGNALL 
and from the centre of the frontal face there is what one might call 
a raised pedestal to take the stem of the third antennal segment 
(PL III. fig. G). The sense-organs, which are presumably present, are 
extremely difficult to see. In certain lights long, colorless bristles or 
filaments may be faintly detected springing from the sides of segments 
four, five and six. At the tip of the apical joint there is a bristle 
nearly as long as the joint itself, whilst, under high magnification, a 
comb-like series of hairs, all equal in length and set close together, 
may be detected stretching from the extreme tip for threequarters (0*75) 
the length of joint, and near the inner edge. The pits from which 
these setae spring touch each other. At the base of this joint, on the 
inner side and in the same line as the series just described, there is a 
single and longer bristle, and opposite, near the outer edge, are two 
moderately large seta-pits (PL III. figs. 4, 5). 
The mouth-cone is broadly rounded and much shorter than its 
breadth at base, scarcely reaching half-way (0*5) across the prosternum 
(PL III. fig. 2). Owing to the dark pigmentation of the head and pro- 
thorax, the mouth-parts of the specimens under consideration are 
somewhat difficult to make out. In one specimen, however, the right 
maxillary palpus is discernible, and on a first examination I was under 
the impression that it was two-jointed as in all the known Tubulifera ; 
but in reality it is composed of only a single joint, as, under the 
highest magnification the seeming segmentation of this palpus takes 
the form of three distinct seta-pits crossing it obliquely near the 
basal third, being the probable seats of a series of sensory filaments 
(PL III, fig. 7). A few touch-bristles (sensory filaments) are found at 
the tip of the maxillary palpus. The labial palpi are somewhat widely 
separated, the form of the palpus being also distinctive. It is apparently 
formed of a single joint, and is slightly constricted towards the apical 
third, the tip being globiform, and only thinly chitinized, having a soft 
and pulpy appearance (PL III. fig. 8). 
Thorax. The thorax and appendages do not exhibit any striking 
peculiarity in structure, excepting that the hind-pair of coxæ are the 
most widely separated. The prothorax is transverse, one-third (0*33) 
broader than the breadth of the head, twice as wide near the base 
as long, and has the surface weakly scabrous. The episternum is not 
fused with the mesothorax, which latter is short, a little narrower than, 
and well-separated from, the prothorax by a deep constriction. It is 
widened to its juncture with the metathorax, and this lateral widening 
is smoothly continued to the basal third of the metathorax, which is 
then slightly constricted to the base of the abdomen. A very short, broad, 
