ADJUSTMENT OF FLATFISHES 421 



much darker. Notwithstanding the justifiabiUty of such a pro- 

 cedure in some cases, I have not taken the Hberty of altering 

 either the plates or the prints by pen or brush, not even (with a 

 few unimportant exceptions) for the purpose of correcting im- 

 perfections or blemishes. I have, however, 'intensified' a number 

 of negatives which had been underexposed. 



In order to supplement these photogr'aphic illustrations, and to 

 give an idea of the actual color of this species in two different phases, 

 I reproduce (plate 6) two water-color sketches by Mr. V. Serino, 

 one of the artists of the Naples station. ^^ The artist has done well 

 with a very difficult subject, but the constant slight changes in 

 the disposition of the pigment of this fish proved to be extremely 

 baffling. Moreover, the specimen chosen for these sketches, of 

 which I have given photographic reproductions in figs. 3a and 36, 

 did not prove to possess the power of color adaptation in as high 

 a degree as did many others. Thus the difference between the 

 'sand' and the 'gravel' phase is not nearly as striking as that 

 shown by some other specimens. {Cf. figures 2e and 2/, plate 5). 



Responses to the various backgrounds 



To commence with the natural backgrounds, we have: 

 1. A rather coarse, mixed sand, consisting of particles of lava, 

 tufa, shells and other materials. The general tone of this 

 sand was very dark, since it consisted largely of jet black particles 

 (probably magnetite, in part), but it contained abundant white 

 and pale gray specks, which contrasted strongly with the rest. 

 This material is of frequent occurrence in the bay, in the vicinity 

 of Naples. Probably the majority of the fishes, as already stated, 

 harmonized fairly well with this sand, when first brought into the 

 laboratory. When kept upon this material, the harmony often- 

 times became quite striking (figs. 2f, 4c, 9a). The resemblance 

 consisted not only in the general similarity of color-tone, but in 

 the granulated appearance of the fish's durface, and the presence 

 of the white specks of the 'annuli' (see p. 414), which matched 



1^ One of the many courtesies for which I have to thank the director of the station 

 was the phtcing at my disposal of the services of Mr. Serino for a number of days. 



