f.fi & I. Smith — Crustacea of the Albatnm 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 PonLophilus 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. 



However 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. 



The large size of the eggs is a marked feature in many of 

 the deep-water Decapoda. The eggs of Eupagurus politus from 

 50 to 500 fathoms, are more than eight times the volume of 

 those of the closely allied and larger E. bernharclus from shal- 

 low water, and in Sabinea princeps, from 400 to 900 fathoms, 

 they are more than fifteen times as large as in S. septemcarinata 

 from 25 to 150 fathoms. The most remarkable cases are 

 among the deep-water genera. Oalacantha rostrata and G. 

 Bairdii, from between 1000 and 1500 fathoms, have eggs 3 mm 

 in diameter in alcoholic specimens, while in the vastly larger 

 lobster they are less than 2 mm . The largest crustacean eggs 

 known to me are those of Parapasiphae sulcatifrons, a slender 

 shrimp less than three inches long, taken between 1000 and 

 3000 fathoms. Alcoholic specimens of these eggs are fully 

 4 by 5 mm in shorter and longer diameter, fully ten times the 

 volume of the eggs of Pasiphae tarda from 100 to 200 fathoms, 

 more than three hundred and fifty times the volume of those 

 of a much larger shallow-water Paicemon, and each one more 

 than a hundredth of the volume of the largest individual of 

 the species. From the peculiar environment of deep-water 

 species it seems probable that many of them pass through an 

 abbreviated metamorphosis within the egg, like many fresh- 

 water and terrestrial species, and these latge eggs are apparently 

 adapted to producing young of large size, in an advanced stage 

 of development, and specially fitted to live under conditions 

 similar to those environing the adults. 



