224 Prof. W. C. M'Intosli on fhe 



protection, but it seems to have been overlooked that many of 

 tlie surface-animals are there only for a limited period durino; 

 fine weather, and disappear into the depths on the advent of 

 storms and cold. Moreover, not a few of the forms disporting 

 themselves at the surface are conspicuously coloured — for 

 exam]ile, the jellyfishes *. 



Protective coloration, by which is meant that hue in harmony 

 with the surroundings, and which, for instance, causes a very 

 young leveret on the approach of danger instinctively to leave 

 the green sward and crouch on the brown earth to escape obser- 

 vation, readies its acme in the transparent tissues of the jelly- 

 fishes. There are, however, many exceptions, and even the 

 most transparent forms by-and-by develop opaque bands (the 

 ovaries and spermaries) just when the existence of the organism 

 is most valuable. The brightly coloured forms again, such 

 as Oceania, Pelagia, Velella, Porpita, and many others, which 

 follow precisely the same habits as the uncoloured and trans- 

 parent, raise doubts as to the validity of the interpretation so 

 generally accepted. These doubts, indeed, find expression in 

 Prof. Moseley's remark tiiat deep blue forms are so coloured 

 for protection. Deep blue jellyfishes, however, form but a 

 small proportion of the vast numbers found in the ocean. 

 Neither are the varied hues of any advantage as warning 

 colours, for the brightly coloured and the translucent (as 

 Beddard remarks) are equally palatable to whales and other 

 forms (not excejiting man) utilizing them for food. The 

 pelagic sea-anemones are also coloured, and the floating stages 

 of others [Arachuactin) are often tinted with white and 

 yellow. 



The brilliant colours of anemones in general cannot be said 

 to be either protective or warning, since on the one hand 

 there is no more deadly bait for cod, and on the other many 

 small fishes swim in comfort in tanks amongst anemones, 

 and in the China Sea a red fish takes shelter in the stomach 

 of an anemone two feet across. Anemones for the most part 

 seem to defy protective coloration, as is sufficiently proved by 

 a glance in the rocky caverns on the eastern shores or along 

 the creeks of the west, where the olive-green tangle-blades 

 and other seaweeds are studded with the opelet {Anthea cereas), 

 whose long trailing tentacles, with their hues of green and red, 

 wave with every surge of the tide. The view that the gaudy 



♦ Beddard observes : — " If transparency of pelagic organisms, according 

 lo Darwin, be due entirely to Natural Selection, it is remarkable that 

 there is so little modilication in this direction amongst the species in- 

 habiting the bottom '' {op. ctt. p. 126). He is inclined to tliiuk that 

 protfctive resemblance may be due to other causes than Natural Selection. 



