ZOOLOGY AND ROT ANY, MICROSCOPY, ETC. 711 



conspicuousness is not a secondary sexual character, and that it serves 

 neither for progressive nor protective resemblance, and then describes a 

 series of experiments made to test its value as a warning character. It 

 was shown by experiment with artificially-coloured Atherinas, which 

 were at the same time rendered unpalatable, that the grey snapper, the 

 commonest predaceous fish of the region, discriminates certain colours, 

 forms associations with great rapidity, and retains these associations for 

 a considerable time (memory). The artificially-coloured Atherinas 

 quickly came to have a warning significance for the grey snapper, and 

 to be avoided even when not unpalatable, although normal Atherinas 

 were still readily eaten. Conspicuously coloured coral-reef fishes were 

 then thrown to the snappers, in their natural environment, but at a 

 distance from the reefs, and all the twenty-one species used were readily 

 eaten. The investigator therefore concludes that these fishes do not 

 possess that combination of conspicuousness with unpleasant attributes 

 necessary to the theory of warning coloration, and that their colouring 

 has no warning significance. Selection has not acted on their colour- 

 ing or other conspicuous characters, but these are the result of internal 

 forces. They are the result of race tendency unchecked by selection. 



In the last part of the paper the author applies his conclusion to the 

 " warning coloration " of insects. He brings evidence to show that 

 vertebrate foes are able to discriminate between palatable and unpalat- 

 able insects without the aid of a distinguishing conspicuousness, and 

 maintains that, since unpalatability must have preceded it, the con- 

 spicuousness cannot have been initiated by selection. The conspicuous- 

 ness has been developed under immunity from selection, and it is 

 therefore to be regarded as an expression of race tendencies, of internal 

 forces unchecked by selection. The author proposes a theory of 

 " immunitv coloration " as a substitute for the theory of warning colora- 

 tion, the former term covering all cases not attributable to selection. 



Cranial Anatomy of Mail-Cheeked Fishes.* — E. P. Allis, jun., 

 describes the skull of Scorpsena in detail, and with beautiful illustra- 

 tions. This is the first instalment of an account of the whole cranial 

 structure in the mail-cheeked fishes. 



Archer-Fish.t — Theodore Gill gives an account of the archer-fish 

 ( Toxotes) and its feats, relying mainly on the observation of Zolotnitsky 

 in 1902, but pointing out the need for corroboration. 



Nuclein Material in Various Stages of Eel.J — A. Panella finds 

 that phospho-carnic acid is a normal component substance in the eel at 

 all stages (after the Leptocephalus-stage) — young, adolescent, and adult. 

 The nuclein content is at a maximum in the youngest (post-larval) 

 stage, and decreases gradually as the animal grows older. 



Nervous System of Lancelet.§ — J. Boeke discusses that part of the 

 ventral cerebral wall of Branchiostoma lanceolatum, which he previously 



* Zoologica, lvii. (1909) lief. 3, pp. 1-72 (3 pis.). 



t Smithsonian Misc. Coll., v. (1909) pp. 277-86 (3 figs.). 



X Atti Soc. Tosc. Sci. Nat , xviii. (1909) pp. 25-30. , 



§ Proc. Acad. Amsterdam Section of Sciences, xi. (1908) pp. 53-9 (1 pi.). 



3 r 2 



