Page:The aquarium - an unveiling of the wonders of the deep sea.djvu/150

Rh 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. Montagn, 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 familiarized to its home by several weeks' captivity.

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 Actiniæ, before the Tank was seasoned. I attribute this immunity to their constant habit of keeping at the