18 PROCEEDINGS OP THE AMERICAN ACADEMY 



color in early races of mankind, from the color descriptions of Homer 

 and early Greek writers. It is not an uncommon thing to find chil- 

 dren of the lower classes unable to give specific names to the different 

 colors ; but, if I am not mistaken, they can always distinguish the 

 primary colors without difficulty, though not able to name them. Cer- 

 tainly, the facility for painting and coloring noticeable in the pottery of 

 the uncivilized races of the world seems unfavorable to this theory. 



EXPLANATION OF THE PLATES. 



The Plates accompanying this paper are a fair sample of the results to he 

 ohtained from the transfer of original drawings by the Heliotype process. The 

 drawings are quite acceptable reproductions of the originals ; and this method of 

 illustrating papers on Natural History will prove very useful in many cases. 

 The method described by the younger Sars for obtaining transfers from original 

 drawings is somewhat cumbersome, requiring a great deal of care and a num- 

 ber of processes. The present method simply requires for the naturalist that 

 he should put on thin Bristol board the plate he desires to have transferred, of 

 the size he wishes, and arranged as he desires ; the only requisite being that 

 the figures be all drawn with a pen and with a special ink. He may then be 

 assured that he will get a plate nearly as clear as his original ; and several 

 transfers being made from the original, — say three or four, — a large number 

 of clear copies can be struck off without reducing the distinction of the im- 

 pressions, as is invariably the case in all lithographic processes. The delay 

 incident to all lithographic processes requiring a special artist are done away 

 with, and the author has only himself to blame for errors. This method seems 

 to give better results than that employed by Sars. Compare his plates of 

 Brisinga with those of the present paper. The cost of the Heliotype method is 

 moderate ; the impression on paper, and whole manipulation, after the drawing is 

 supplied to the patentees of the process, being considerably less than the cost 

 of printing and paper from an ordinary lithographic stone. 



Plates III., IV., V., figs. 1-5, illustrate the development of a dextral Flounder, 

 in which the eye passes from the left side to the right side. 



Plate V., figs. 6-13, Plate VI., illustrate the development of a sinistral 

 Flounder, in which the eye passes from the right side to the left. 



Plate VII. illustrates the development of a sinistral Flounder, in which the 

 eye passes from the right to the left side long before the dorsal, anal, or caudal 

 fins have lost their embryonic character. 



Plate VIII. illustrates the changes of color produced in the young Flounders 

 by placing them on differently colored ground. 



Plate IX. shows the development of a sinistral Flounder, in which the ante- 

 rior part of the dorsal becomes to some extent an anterior dorsal. 



Plate X. illustrates the passage of the eye through the integuments between 

 the base of the anterior part of the dorsal and the frontal bone. 



