246 MB. w. BATESON ON COLOUE- [Mar. 6, 



His Excellency the Governor brought, I think, some 20 or 30 

 skins home. Messrs. Swanzy's agent, with whom I travelled home, 

 was bringing some more which he thought might be commercially 

 valuable, but which have turned out useless, and I obtained altogether 

 125. With these exceptions I never heard of any being brought 

 from the Gold Coast. Very few of the Europeans in Accra to whom 

 T showed them had seen them before, and I hear my hunters declined 

 to get any more : but when I go back to Accra I shall obtain some of 

 the different varieties, now I know where to get them and also 

 know that they are worth getting, for that the hilly countries of 

 the two Akims and Aslianti — to say nothing of other districts — are 

 full of them there can be no doubt. 



I think from what I could gather that these orange-marked ones 

 are in the nature of an albino variation, for the marks vary in size 

 and brilliancy, some of them being quite small, while others cover 

 the whole skin. 



The habitat, food, and habits of these varieties are exactly the 

 same as those of the black species, among which they are found. 



5. On two Cases of Colour-variation in Flat-fishes illus- 

 trating principles of Symmetry. By W. BatesoNj M.A., 

 Fellow of St. John^s College, Cambridge. 



[Received March 6, 1894.] 



(Plate XVII.) 



The two cases of Variation here described are both examples of 

 abnormal deposit of pigment in the skin of the normally 

 uupigaiented or " blind" side of Flat-fishes. The two cases are 

 unlike each other, but both are remarkable illustrations of the ways 

 in which the phenomenon of Symmetry may be manifested and 

 may contribute to the production of a definite result in Variation 

 that is presumably sporadic. 



The first specimen is a small Brill (Rhombus Icevis), kindly sent 

 to me by Mr. Matthias Dunn, of Mevagissey, Cornwall. It is 9| 

 inches long, and 6| inches wide in the widest part. The dorsal fin, 

 the eyes, and other parts are normal in foi-m and position. The 

 only abnormality seen consists in the presence of a row of five 

 spots of colour along the dorsal border of the body on the blind 

 side, and of another row of three spots along the ventral border on 

 the same side. The spots are on the body, central to the dorsal 

 and anal fins, which are both of normal colour. The interest of 

 the case lies in the remarkable symmetry with which the spots 

 are distributed with reference to the longitudinal axis of the body. 

 On reference to the plate (Plate XVII.) it will be seen that each of 

 the three ventral spots stands at very nearly the same transverse 

 level as one of the spots of the dorsal series. The two anterior 

 spots of the dorsal series have no representatives in the ventral 

 series. This appearance of symmetry, so striking to the eye, is 



