EFFECTS OF DARKNESS 155 



anemones with which it is commensal. The other 

 crustaceans who live in company with this Parapa- 

 gtirus (but without any sea-anemone messmates) must 

 be almost or quite blind, since their eyes have become 

 dull and opaque, and have lost nearly all their colour ; 

 such are Glyphocrangon ccBcesce7is, Pontophihis abyssi, 

 and the species of Munidopsis. In Willemoesia forceps^ 

 a sort of fragile lobster, which also lives in this 

 abyssal locality, the degradation of the eyes has gone 

 even further, for they have become completely colour- 

 less, while the eyestalks are immovably affixed to the 

 carapace. Two species of prawns [Dorodotes reflextts 

 and Acanthephyra microps), complete the list of crus- 

 taceans which we have dredged on our abyssal plain : 

 their eyes, though small, and though a little paler 

 than those of their congeners, are still well-formed 

 and serviceable, but there is considerable doubt as to 

 whether these species really live on the bottom, or 

 ascend and descend in the gloomy canopy above. The 

 same doubt applies to the two fishes of the Ophidioid 

 genera Neobythites and Dermatorus, which we twice 

 found in the trawl when dredging at a depth of nearly 

 1750 fathoms. But the blind mollusk which we 

 brought up from 1803 fathoms must have come from 

 the bottom, seeing that it is a bivalve closely related 

 to the scallops of shallow water : it has been named 

 Amussium solitarium by Mr Edgar Smith. 



One of our three hauls on this passage across 



