80 NOTES ON DERWENT ESTUARY FISHES, 



b. Pale violet-brown, in parts tending to cream^ 



with the transverse bars prominently show- 

 ing; seven in all. In certain of the young 

 this tendency to lightly marked areas is con- 

 centrated upon the posterior half, while it is 

 almost white in two specimens. 



c. Hufous, deep brown, and pale cream in about 



equal proportions, and disposed over the 

 whole head, trunk, and tail indiscriminately. 

 In the specimen with the mark c the bars are 

 quite absent, and the distribution of the pig- 

 ment has become so erratic as to form bold 

 confluent blotches of irregular shape instead 

 of bars, and with no likeness to them. 



d. It is almost white ; delicate creamy white, 



with a slender indication of obsolete brown 

 pigment marks. 



The evolution of phase c with its rufous and blotching 

 belongs to an aberrant rather than a normal stage. This 

 fusion of v/hat should be regular bands of pigment is also to 

 be seen in a younger specimen, though in a much less 

 degree. 



In the young measuring between 1.2 and 2.5 inches 

 there are two types, and their after development appears 

 to be based separatelv upon the two-colour schemes — - 



a^ Young similar to a (adult). 



b^ Young similar to b (adult). 



Here we have a dark phase and a pale phase with trans- 

 verse bars. The bars in the young are broken midway. 



There is distinctly a violet tinge on all the brown 

 parts, while some specimens of 1.2 inches in length are 

 richly diffused with it and completely over the animal ; the 

 bars showing. 



With age the dark pigment either disappears, the 

 fish assuming the pale phase, or the species is dimorphic. 

 This latter is indicated in many of the young specimens 2.5 

 inches in length. 



