132 
THE VOYAGE OF H.M.S. CHALLENGER. 
logically it belongs to the cirrus-group. In its interior are many bands of fibres, 
apparently muscular. 
The scales seem to amount to fifteen pairs, and are whitish and semitranslucent. 
They are borne on very prominent papillae, which project in a divergent manner along 
the dorsum, and with the branchiae give a remarkably rugose aspect to the region. They 
occur on the second, third, and fourth feet, on the sixth, eighth, and alternately to the 
twentieth, then on twenty-third, twenty -eighth, twenty-ninth, and some of the succeed- 
inof, the latter beinn small and much modified. The anterior scales are somewhat rounded 
and marked by a deep notch externally (PI. XXIV. fig. 3), or occasionally with a rudi- 
mentary papilla ; while behind the foregoing region of the body a tongue-shaped process 
springs from the bottom of the notch, so as to give a peculiar character to the scale. The 
fourth scale is large, and elongated from before backward ; and the fifth is irregularly 
cjuadrate. Posteriorly the organs are small, but they may be in process of development. 
The surface is quite smooth, with traees of hypodermic areolm. In vertical section the 
cuticle of these organs is attenuate, and the intermediate hypoderm very thin. 
The feet (PI. XXIV. fig. 2) are thirty-four in number, and the majority are pro- 
minent and rather massive structures. The first pair, as already mentioned, are 
directed forward, each carrying the tentacular cirri superiorly on a special process, which 
has a papilla at the base of the fork, from which the bristles emerge. The special process 
at first sight appears to represent the ordinary dorsal cirrus, but a closer scrutiny reveals 
two spines (one to each cirrus) in the soft tissues, so that it really indicates the setigeroiis 
lobe of a foot. A tuft of simple slender bristles comes from each division. 
The second foot (which from the ventral surface appears to be the first) has superiorly 
a single bristle with its shaft more slender than the others near it, and with an abruptly 
narrowed tapering tip which has a series of elongated spines on one side. Those beneath 
are simple bristles with a well-marked wing at the tip, which is bent at a very consider- 
able angle to the shaft. The centre of the foot is occupied by a powerful dark brown 
spine, which in all is broken off as it emerges from the skin. A process which appears to 
be the ventral division has a few slender smooth bristles similar to those in the first foot. 
The ventral cirrus is greatly developed, the base being enlarged and the tij) somewhat 
bulbous, the latter, moreover, being slightly differentiated. 
The next foot (third) resembles the former, but shows two of the dark brown spines 
projecting through the skin. The superior group consists only of slender simple bristles, 
and stumps of larger .ones. The middle and lower regions have many of the winged forms, 
while ventrally, between the latter and the cirrus, are groups of slender simple bristles as 
in the second foot. The ventral cirrus is now more slender, but presents the same 
differentiated clavate tip. This foot also bears a dorsal cirrus. 
As we proceed backward the fissure between the dorsal and ventral divisions of the 
foot enlarges, partly from the increase of the former in an outward direction. At the 
