AZURINE. DOBULE. 47 



gZURINE. 



THE Rudd, like fish generally, is subject to variety, and it would appear that the Azurlne, 

 or Blue Roach, first described by Yarrell under the name of Leuciscus cccridcus (Lin. Soc. 

 Trans, vol. xvii. p. i. p. 8), is merely a variety of the Rudd. At the time Yarrell obtained 

 specimens of the Graining from some of the Knowsley waters through the kindness of the 

 Earl of Derby, he received also specimens of fish which he called the Azurine or Blue 

 Roach. Through the kindness of Mr. T. J. Moore, of the Liverpool Museum, I have been 

 able to examine a great number of these Azurines which came from the Knowsley pools ; 

 of course, having been for many years in spirits, they have lost their original blueness of 

 colour. The position of the dorsal fin relative to the ventral, the narrow oblique mouth, 

 and above all the serrated throat-teeth, which in no respect differ from those of the Rudd, 

 all point to the conclusion that the Azurine is a variety of the Rudd or Red-eye. As to 

 colour it is never safe to depend much on any peculiarity; we would do well to remember 

 the admonition of the Roman Poet — -"nimium ne crede colori." I am informed that these 

 Azurine fish are not now found in the Knowsley ponds. The specimens in the Liverpool 

 Museum are all of a small size, few being more than six or seven inches in length. 



UoBULE. 



THE Dobule Roach, a single specimen of which Yarrell took with the mouth of a White- 

 bait net in the Thames below Woolwich, and which is regarded by Giinther as a small 

 Dace, is thus in its principal characteristics described by Yarrell: — "Body slender in pro- 

 portion to its length; nose rather rounded, upper jaw longest; ventral fins arise just in 

 advance of the line of the origin of the first ray of the dorsal fin ; tail considerably forked ; 

 scales of moderate size, fifty forming the lateral line; the colour of the top of the head, 

 nape, and back dusky blue, becoming brighter on the sides, and passing into silvery white 

 on the belly; dorsal and caudal fins dusky brown; pectoral, ventral, and anal fins pale 

 orange red; irides orange; cheeks and operculum silvery white." 



The Lciiciscus dobula of Agassiz, Cuvier and Valenciennes, is given by Giinther as a 

 synonym of the Leucucus cephalus, or Chub. 



