THE PHYSIOLOGY OF DEEP-SEA LIFE. 309 
should be stung by large lasso-cells. According to fishermen, 
fishes avoid nets when filled with phosphorescent animals; yet 
on coral reefs fishes are constantly seen browsing upon the 
corals and shoals of gorgonians. The commensalism of many 
acalephs and quite delicate fishes living surrounded by the ten- 
tacles of medus:e, and especially by the intensely burning ten- 
tacles of Physaliæ, would seem to prove that they are not in 
dread of lasso-cells. 
During the voyage of the * Challenger," Professor Moseley * 
made a series of spectroscopic observations on the coloring-mat- 
ters of various deep-sea invertebrates. Special attention was 
paid to spectra presenting isolated bands, because they are read- 
ily identified. He says :— 
“ Peculiar coloring-matters giving absorption spectra have now been 
found to exist in members of all the seven groups of the animal king- 
dom. Amongst Protozoa such coloring-matters occur in Infusoria and 
Sponges; amongst Coelenterata they occur both in Anthozoa and Hy- 
dromedusæ, in Echinodermata, in both Crinoidea, Echinoidea, and 
Holothuroidea, but not in the Asteroidea. In Vermes, in Annelids 
and Gephyreans. In Arthropoda, in Crustacea and in Insecta. In 
Mollusks, in Gasteropods only. In Vertebrata, in four fish, three spe- 
cies of Odax and one Labrichthys, and twelve birds of two closely 
allied genera. The Echinodermata and Coelenterata appear to be the 
groups which are most prolific of such coloring-matters. Pentacrinin 
and Antedonin seem to be widely diffused in immense quantities 
through the tissues of the erinoids in which they oceur; and Echino- 
derms generally seem to be characterized by the presence of evenly 
diffused, abundant, and readily soluble pigments. 
“Tt seems improbable that the eyes of other animals are more per- 
fect as spectroscopes than our own, and hence we are at a loss for an 
explanation, on grounds of direct benefit to the species, of the exist- 
ence of the peculiar complex pigment in it. That the majority of spe- 
cies of Antedon should have vivid coloring-matters of a simple charac- 
ter, and that few or one only should be dyed by a very complex one, is 
a remarkable fact, and it seems only possible to say in regard to such 
facts, that the formation of the particular pigment in the animal is 
accidental, 4. e., no more to be explained than such facts as that sul- 
phate of copper is blue.” 
Professor Moseley also observed that the phosphorescent light 
1 Quart. Journ. Mic. Science, XVIIL., 1877, p. 1. 
