56S. L. Smith—Crustacea of the Albatross Dredgings. 
are not conspicuously smaller than in many allied shallow- 
water forms. In 1 the eyes are black but conspicuously 
smaller than in the allied shallow-water species. In 13 the 
eyes are black and of moderate size. In 9 they are apparently 
black or nearly black and small. In 2 they are nearly color- 
less in alcoholic specimens and rather larger than usual in the 
genus, but considerably smaller than in Pontophilus gracilis, a 
very closely allied species found in 200 to 500 fathoms. In 7 
and 8 they are small and light colored. In 10 they are rather 
small and dark brown. In 14, 15 and 16 they are not con- 
spicuously different in size from those of allied shallow-water 
species and are dark brown. 
wever strong may be the arguments of the physicists 
against the possibility of light penetrating the depths from 
which these animals come, the color and the structure of their 
eyes, as compared with blind cave-dwelling species, show con- 
clusively that the darkness beneath two-thousand fathoms of 
sea-water is very different from that of ordinary caverns. 
While it may be possible that this modification of the darkness 
of the ocean abysses is due to phosphorescence of the animals 
themselves, it does not seem probable that it is wholly due to 
this cause. 
Nt he ee 3 
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