112 
THE VOYAGE OF H.M.S. CHALLEHGEE. 
The head is shaped somewhat like that in Lepidonotus, with the bases of the antennse 
elevated dorsally and nearly on a level with the same ]Dart of the tentacle. Two smaller 
eyes are placed quite at the margin posteriorly, and a much larger one on each lateral 
eminence. A small lens-like whitish speck occurs in the middle of each of the former, 
and a similar structure lies toward the anterior part of the latter, being thus eccentric 
in position and probably connected with anterior vision. The base of the tentacle is 
large, and tapers little distally ; while the column of the organ is longer than the palpi, 
and nearly of uniform diameter, though rather larger p,t the distal than the proximal end. 
A filiform process occurs distally. The antennae are of considerable length and similar 
in shape. Their filiform terminations almost reach the tips of the palpi. The tentacular 
cirri agree in shaj)e with the tentacle, being very slightly increased in diameter from base 
to tip. The anterior dorsal cirri are similar, but they soon assume a flattened, broadlv 
fusiform or lancet-shape below the filiform process, till near the posterior end of the body, 
when they become more slender distally. A symmetrical pair terminate the body. All 
are quite smooth. The palpi are comparatively short, finely tapered at the tip, and also 
smooth. There is a short cylindrical j>rocess in the median line dorsally, over the oral 
aperture, as in certain other forms {e.g., Eulagisca corrientis, p. 91) and as indicated by 
the rounded boss in Lepidonotus squamatus. The ventral cirrus is a subulate tapering 
organ, reaching nearly to the base of the bristles. The ventral papilla is a well-marked 
cylindrical process, slightly enlarged below the tip as in Lepidonotus. It is, however, 
considerably shorter than the latter. 
The scales are about twenty-three pairs. They are somewhat ovoid (PI. XIX. fig. 3) 
and comparatively smooth, a region along the outer border, however, having a series 
of closely arranged minute blunt tubercles rather than spines. The scar of attachment 
is outside the median line, and is indicated on the scale by a pale spot. The latter, in the 
last scale, is near the anterior border, which is inflected. The rest of the surface of the scale 
is pale brown, with four darker longitudinal belts which join those of the preceding and 
succeeding scales, so that the four stripes are continuous from head to tail, the outer pair 
having the pale area of attachment between them. In vertical section the thickest part of 
the scale seems to be at or rather around the scar of attachment, and it tapers conspicuously 
in its inward progress, less so externally. The dorsal cuticle of the scale is thicker than 
the ventral. The intermediate hjqDodermic layer is comparatively thin and firm. 
The dorsal division of the foot is very little developed, being represented only by a 
small papilla, from which the spine does not protrude. On one side of the papilla are a 
few minute bristles (PI. IXa. fig. l), the shorter forms are probably homologous with those 
occurring near the body in the ordinary types, while the longer example with a tapering 
extremity probably indicates an average specimen. The spinous rows are well marked. 
The bristles of this branch of the foot somewhat resemble such imperfectly developed 
kinds as are found in Harmothoe mmphysce. 
