A. Agassiz says in his reports on the dredging operations on the west coast of America: ‘The coloration of the deep-sea fishes is comparatively monotonous. The tints are all a light violet base, tending more or less to brownish or brownish yellow, or even to a greenish tint, especially among the Macruridæ. Some of the Liparidæ were of a dark violet, and one species was characterised by a brilliant blue band. The Ophidiidæ, _Nemichthys_, and the like, are usually of an ashy violet tint, while in _Ipnops_ and _Bathypterois_ the tints were of a decidedly yellowish brown.’ That the deep-sea fish are usually devoid of any pronounced spots, stripes, and other markings, is now well recognised. It may not be altogether out of place, however, to refer briefly to a few exceptions. The black circles on the abdomen of _Neoscopelus macrolepidotus_ have already been referred to. _Halosaurus johnsonianus_, has a black spot on the tail. _Aulostoma longipes_ has three pairs of large black spots on the ventral side, but the specimen taken in 1,163 metres of water by the ‘Talisman’ was probably a young one. It is very probable that in all the exceptional cases, when fish taken in deep-sea water have exhibited such spots and markings, they are examples either of fish that have quite recently adopted an abysmal habitat or of young specimens exhibiting ancestral inherited characters. In referring to a specimen of _Raja circularis_, taken by the ‘Triton’ in 516 fathoms, Günther says: ‘It is notable that the spot on each side of the back which in littoral specimens is variegated with yellow is much smaller in the deep-sea specimen and uniformly black without yellow.’ It seems to be then a very general rule among fishes that as they migrate into deeper water the spots and stripes, so conspicuous among many forms living on the surface and in shallow water, disappear, and the coloration of the body becomes more evenly distributed and uniform. Among the Mollusca, the deep-sea Cephalopods seem to be usually violet, but an _Opisthoteuthis Agassizii_ caught by the ‘Blake’ is stated to be of a dark chocolate colour, a _Nectoteuthis Pourtalesii_ reddish-brown, and a _Mastigoteuthis_ orange brown, while of the specimens brought home by the ‘Challenger,’ _Cirroteuthis magna_ was said to be ‘rose’ when captured, and the spirit specimens of _Cirroteuthis pacifica_ and _Bathyteuthis abyssicola_ were purplish madder and purplish brown respectively. The shells of the Gasteropods and Lamellibranchs living in the abyss are frequently so thin as to be almost transparent, and are, with very few exceptions, white or pale straw coloured. The colour of the only specimen of nudibranchiate Mollusca that has been found in the abysmal zone, namely, _Bathydoris abyssorum_, is described by Mr. Murray as follows: ‘The body of the living animal was gelatinous and transparent, the tentacles brown, the gills and protruding external generative organ orange, the foot dark purple.’