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W. T. CALMAN. 
reason for attributing any profound morphological signifi- 
cance to these supernumerary segments of the peduncle. 
Antenna. — Chappuis points out that the peduncle consists 
of three segments, a short basal segment preceding the two 
figured by Vejdovsky. In this case there can be no question 
that Chappuis^ observation is correct, the additional segment 
being well defined both proximally and distally (Text- fig. 7). 
The character is possibly of importance, since in the other 
living Syncarida, as in most Malacostraca, only two segments 
are present. In this respect Bathynella agrees with the 
Mysidacea and many other Peracarida. The third segment 
Text-fig. 7. 
Bathynella natans, $. Antenna of left side, dorsal view. 
bears a small unsegmented exopodite tipped with two setae, 
and is followed by a flagellum of five elongated segments. 
Mouth -parts. — The mandible (Text-fig. 8, md.) has a 
palp of three segments, of which the second is much the 
longest. The oral edge is irregularly toothed, and its 
proximal part, which would correspond to the molar process, 
is thin and sharp-edged. The lower lip (Text-fig. 2, mt.) is 
large, as in other Syncarida, and its lobes appear to terminate 
each in a minute inturned point. 
The maxillula (Text-fig. 8, mx/) is incorrectly figured by 
Chappuis. It has two endites, the proximal small and 
bearing two apical setas, the distal armed with a group of 
spines. A rounded distal eminence on the outer side, bearing 
three setas, no doubt represents a vestigial palp. The whole 
appendage bears an unmistakable resemblance to that of 
Koonunga as figured by Sayce (1908, PI. I, fig. 12). No 
