in the Depths of the Sea. 441 



and G. horrida are red. Many of our deep-water Mysidea, 

 among them Pseudomma rosenm, are strongly rose-red, with a 

 shade of orange or violet ; and many more animals. All the 

 Rhizopoda are white. Echinocucumis typica, nearly all the 

 Polyzoa, and most of the higher mollusks (of which perhaps 

 the colour of a sufficient number has been given above). 



Although the red and white colours are thus predominant 

 at these great depths, other colours are by no means absent. 

 Thus Actinopsis jlava is entirely yellow, Lcetmonice jilicornis 

 has there, as in shallow water, shining yellow foot-brushes. 

 The limbs of the three species of Gythereis mentioned are all 

 yellow. The sarcode of Cristellaria rotidata is light citron- 

 yellow. Phascolosoma olivaceum is dark olive-green. Umbel- 

 lisyUis fasciata has interrupted olive-green cross bands on the 

 back. Ctenodiscus crispatus is light reddish brown. Ophiura 

 ahyssicola and Ophiacantha spinulosa are grey or chestnut- 

 brown and spotted ; Antedon Sarsii more or less brown, with 

 small yellow or brown-red blisters along its tentacular grooves ; 

 and Eurycope furcata has a singular yellow-brown cross band. 

 Molpadia borealis is dark-brown violet, Hornera violacea pale 

 violet. 



It has been generally supposed that light could only pene- 

 trate into the sea to a comparatively small depth, since, ac- 

 cording to the late experiments of Bouger and Lambert on the 

 absorption of light in water, all trace of it disappears at 120 

 fathoms under the surface. Late discoveries of the existence 

 of many coloured animals at much greater depths (since, as I 

 have said, colour is held to stand in close relation to light) 

 agree very little with these experiments, which are further 

 contradicted by another fact learnt on our coast. Not only at 

 the depth of 300 fathoms, but even of 450 fathoms, have been 

 found living animals (e. g. Pasiphae norveyica, Pontophilus 

 norvegicus, Gryptocheles ahyssicola, and others) possessing 

 perfectly developed organs of vision, which could be of no use 

 (since nature does nothing in vain) if in those depths of the 

 sea there reigned such absolute darkness as exists in those 

 subterranean caves whose inhabitants we find to have no eyes. 

 It is much to be regretted that we have yet no certain know- 

 ledge as to how far light penetrates down into the sea, or its 

 mode of transmission there, or other physical facts connected 

 with it. 



I add, lastly, that the many new animal forms referred to in 

 the present paper, of which some are very remarkable, will all, 

 as the collected materials are by degrees worked out, and as 

 soon as possible, be described and published. 



