328 
THE VOYAGE OF H.M.S. CHALLE^^GEE. 
tentacle is flanked by two long lateral tentacles. The two inferior (or external) lateral 
tentacles are stouter and generally slightly longer than the median, though in one 
specimen the organ of one side is the longest process of the kind on the head. There 
would, indeed, apj)ear to be considerable variety in regard to the cephahc processes. 
One specimen shows short tentacles throughout, with the exception of the long inferior 
lateral just mentioned. Another presents a bifid median tentacle, the ringed base 
splitting into a larger and a smaller division at the summit ; three rings, moreover, being- 
apparent at the commencement of the former, and one on the latter. It would seem 
that when injury occurs to several of the tentacles, those remaining (especially the 
inferior or external lateral) are especially elongated and enlarged. Two short and l^luntly 
conical frontal tentacles occur anteriorly. The lateral palpi are prominent and rounded. 
The buccal segment has dorsally two rather short tentacular cirri, the ti]3s of which 
reach, in those best developed, the bases of the cephalic tentacles. Moreover, in one 
example, the left side has two instead of one, both, however, being smaller than the 
right cirrus. The pair arise close together, apparentl}^ from a common base. 
The dental ajDparatus (Fig. 81) is dull brownish, with a dark band in front of and 
between the posterior appendages. The maxillae are almost in the same plane with 
the latter, and are characterised by their shortness, the great breadth of the posterior 
region, and the strength of the short and strongly curved fangs anteriorly. The posterior 
appendages are constricted at the base (next the maxillae), and have a more or less 
dilated margin, which is sometimes notched. The variability of the thinner marginal region 
(Fig. 82) seems to be a common feature, the firmer basal median part being triangular. 
The left great dental plate agrees with the preceding in the absence of the long anterior 
fang, and has nine or ten teeth ; the right possesses ten. The left lateral paired 
plate shows six and the unpaired ten ; the right has nine teeth. A single and somewhat 
quadrate accessory plate occurs on each side, the inner edge rising as usual into a tooth. 
The mandibles (Fig. 83) show an irregularly denticulated anterior or cutting edge, the 
distal portion being separated from the basal by a transverse line and a prominent 
external margin. The latter condition, so often seen, may be connected with the repro- 
duction of the tip. The mandibles are ankylosed at the dental junction, and a slightly 
marked pigment-line occurs along the margin of the crescent. Two blackish stripes 
occur interiorly, one on each side of the dental symphysis. 
The first region of the body consists of three segments, each having a thickish dorsal 
cirrus, constricted at the base, and a ventral eirrus, only a little shorter and of similar 
form. The setigerous lobe has a short, conical, posterior process. These feet bear 
superiorly a few simple, tapering bristles, and interiorly a jointed bifid series 
(PI. XXVIa. fig. 5) with guards at the tips.' The distal process is large and blunt, 
the inferior shorter and more acute. The articulation occupies the usual position, but is 
less differentiated, perhaps, than in the previous species. 
