SENSATION. 99 



Sanderson, Cossar Ewart, and Mr. W. D. Scott, I have 

 corroborated M. Fredericq's observations by a number of 

 experiments ; stimulation of one eye alone by means of light 

 produces immediate unilateral flushing of the whole of the 

 same side of body, but no change of colour beyond the median 

 line. 



As further proof that a well-developed sense of colour 

 occurs in some of the Arfciculata, I may allude to the experi- 

 ments of Sir John Lubbock on the Hymenoptera; but as 

 these have been already twice published in the International 

 Scientific Series,* I need not here wait to recapitulate them, 

 and shall therefore only remark that it is without any rea- 

 sonable question to the presence of this sense in insects that 

 we owe the beauty both of floral and of insect coloration. 

 Again, as further proof that a well-developed sense of colour 

 occurs in Fish, I may remark that the elaborate care with 

 which anglers dress their flies, and select this and that com- 

 bination of tints for this and that locality, time of day, &c., 

 shows that those who are practically acquainted with the 

 habits of trout, salmon, and other fresh-water fish, regard the 

 presence of a colour-sense in them as axiomatic. And, with 

 reference to the sea-water fish in general, we have the highly 

 competent opinion of Professor H. I^. Moseley to the effect 

 that the great majority of the colours of marine animals 

 have been acquired either for the protection or the allure- 

 ment of prey, and that they refer particularly to the eyes of 

 Fish, and also to those of Crustacea.! 



The fact that a sense of colour occurs in Birds is unques- 

 tionable, and meets with its most general proof in the more 

 or less conspicuous coloration of the fruits on which they 

 feed ; for as in the analogous case of conspicuously coloured 

 flowers depending on insects for their fertilization, so con- 

 spicuously coloured fruits depend for the dissemination of 

 their seeds upon being eaten by birds or mammals. Again, 

 I have already mentioned the fact that nowhere in the 

 animal kingdom does the protective and imitative colouring 

 of animals attain to such nicety as it does where the eyes 

 of birds are concerned. Lastly, the elaborate coloration of 

 birds themselves, and the pleasure which some species take 

 in the decoration of their nests, constitute supplementary 



* Viz., in Ants, Bees, and Wasps, and in Animal Intelliqenee. 

 t Quarterly Journ. Micro. Science^ New Series, vol. xyii, pp. 19-22. 



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