ITS ADHESIVE POWER. 109 



probably connected with the passions. When it 

 seizes its food, especially if it is a living prey, the 

 general hue is a dull bluish black, nearly uniform, but 

 occasionally varied with slight cloudings of a deeper 

 tint of the same colour. At other times, when lying 

 still, the body is of a pale pellucid brown, with drab 

 clouds, and patches of white specks. The first 

 dorsal is always of an orange-fawn colour. The eyes 

 are striking, being of a pale blue, exactly like two 

 turquoises. 



It is a characteristic of the fishes of this genus that 

 the ventral fins are soldered together, as it were, by 

 their inner edges, so as to form an oval disk. The 

 object of this is the adhesion of the , body by means 

 of a vacuum. Col. Montagu, indeed, says of this 

 species, — " In no instance have we observed that they 

 adhered either to rocks or to the bottom of the glass 

 vessel in which they have been kept alive for several 

 days."* But I have seen the Black Goby adhering to 

 the glass sides of my Aquarium by its ventral sucker 

 repeatedly, though not until it had become familiar- 

 ized to its home by several weeks' captivity. 



THE GREY MULLET. 



Some half-dozen Mullet-fry, from an inch to 1^ 

 inch long, proved very hardy, surviving apparently 

 uninjured, even when the exudations from the putty 

 and paint killed everything else, even the Actiniae, 

 before the Tank was seasoned. I attribute this im- 

 munity to their constant habit of keeping at the sur- 



* MS. quoted in Tan-ell's Br. Fishes, i. 283. 

 L 



