94 
THE VOYAGE OF H.M.S. CHALLENGER. 
pale greyish-yellow, with scattered large (nearly 12 mm. in diameter), roundish, annular 
or irregular, brown-grey and black patches ; the largest of these were on the back 
proper ; the annular chiefly on the border of the mantle. The fundamental colour of 
the lower side of the mantle-border paler than that of the upper side. This funda- 
mental colour was, however, replaced in the inner two-thirds by large brownish-black, 
mostly confluent patches, which therefore formed a broad band, interrupted here and 
there ; and this, again, then formed irregular broad tongues, running here and there 
outwards and inwards above the sides of the body ; small scattered patches, mostly a 
little paler in colour, were visible on the outer third of the lower side. The sides of 
the body are yellowish and blackish; the pedal sole principally black and blackish-brown, 
the sides and the margins yellowish ; the upper side of the foot and of the tail like the 
sides of the body. The head of the same colour, but paler ; the tentacles yellowish. 
The stalks of the rhinophores black-brown, with whitish terminal papilla. The gill 
dirty yellow and blackish-brown speckled ; as also the anal papilla. 
The shape of the animal as usual — roundish and depressed. The back itself was 
arched, with a broad, soft mantle-border, which was much broader (20 mm.) behind 
than before (10 mm.). The whole upper side of the animal was thickly covered up to 
and upon the margins of the rhinophore-openings and of the branchial fissure, with 
small (diameter '5 mm. or less), slightly projecting, sessile, rounded nodules (PI. II. 
fig. 1). The marginal portion of the mantle-border soft, strongly bent up and down, 
somewhat indented here and there ; the lower side smooth, showing whitish reticulate 
marks shining through it under the magnifying glass. The (contracted) rhinophore- open- 
ings are situated at the points of knobs, which project about 1‘5 mm., and are scalloped ; 
the rhinophores themselves have a strong stalk, amounting to nearly a third of the whole 
height, the strong club has about forty broad leaves (on either side). The branchial 
fissure lies on the top of a knob, similar to that of the rhinophores, and is also scalloped, 
the scallops being again serrated. The gill is composed of six very strong tripinnate 
pinnae. The (3 mm.) high cylindrical anal papilla is slender, truncated above, with a 
scalloped margin ; the renal pore lies in front to the right, at the base of the anus. The 
head is small, with smaller finger-shaped tentacles ; the outer mouth strongly contracted. 
The sides of the body are quite low ; the strongly-contracted genital papilla in the usual 
place. The foot is strong and broad, the corners of the anterior end rounded, the posterior 
end somewhat narrowed and rounded ; the anterior end has a tolerably deep furrow, 
the rather broad upper lip is fissured in the mesial line; the tail is about 4’5 mm. long. 
The viscera are not visible through the body-wall at any point. The (pseudo-) 
peritoneum is colourless. 
The central nervous system was rather flattened ; it was with some difficulty 
separated by dissection from its loose but adherent capsule, and even then it was not 
easy to distinguish the ganglia, owing in part to their coarsely nodular structure. The 
