62 THE FAUNA OF THE DEEP SEA 



notable that the spot on each side of the back which 

 in littoral specimens is variegated with yellow is 

 much smaller in the deep-sea specimen and uniformly 

 black without yellow.' 



It seems to be then a very general rule among 

 fishes that as they migrate into deeper water the 

 spots and stripes, so conspicuous among many forms 

 living on the surface and in shallow water, disappear, 

 and the coloration of the body becomes more evenly 

 distributed and uniform. 



Among the Mollusca, the deep-sea Cephalopods 

 seem to be usually violet, but an Opisthoteuthis Agas- 

 sizii caught by the ' Blake ' is stated to be of a dark 

 chocolate colour, a Nectoteuthis Pourtcdesii reddish- 

 brown, and a Mastigoteuthis orange brown, while of 

 the specimens brought home by the ' Challenger,' 

 Cirroteuthis mayna was said to be ' rose ' when cap- 

 tured, and the spirit specimens of Cirroteuthis pacifica 

 and Bathyteuthis abyssicola w r ere purplish madder 

 and purplish brown respectively. 



The shells of the Gasteropods and Lamellibranchs 

 living in the abyss are frequently so thin as to be 

 almost transparent, and are, with very few excep- 

 tions, white or pale straw coloured. The colour of the 

 only specimen of nudibranchiate Mollusca that has 



