Such patience as these finny housekeepers manifest is not appreciated by man. The gleaners of the golden fields, in whose waters our little friends are found, have not discovered their secret, and think the curious piles the washes of the brook itself. But their purpose is the protection of their eggs. In swift-running streams, which these fish are so wont to affect, the eggs would be washed away, and, driven against rocks and snags, would be destroyed, or, even escaping destruction, would, by the undulating movement to which they would become subjected, be rendered impossible of incubation. Besides, were they not thus protected, even though there was no danger of being washed away, they would become easy prey to the attacks of carnivorous fishes. Unlike as the Lamprey-eels are in structure to the Dace, yet in their habits of erecting a nest they are very similar. Upon our Eastern sea-board they are a common species, inhabiting both salt and fresh water. In the early spring they follow the shad up the rivers, occasionally preceding them, and search about for suitable localities in which to deposit their spawn. They clean away the stones as the Dace were seen to do, bending their long bodies in coils, which they use in pushing aside the accumulation on the bottom. To the unlearned the appearance of two Eels, each three feet in length, twisting and seemingly coiling about each other, would be indicative of war. But having cleaned for themselves a smooth spot, the Lampreys proceed to place stones. Irregularly-shaped stones of small size are easily and quickly transported in their mouths, but when stones that weigh several pounds are to be brought, the tactics they adopt are worthy of an engineer. As the spots chosen for the rearing of their submarine castles are ordinarily subjected to a swift current, the largest stones, which it would be thought impossible for them to move, are looked for up stream. A suitable one found, and a favorable position presented, the sucking mouth is fastened to it, and by a convulsive effort, the tail of the fish being raised aloft, the heavy stone is lifted from its place, the current pushing against the fish and stone, bearing them along several feet before they sink. Another effort of the fish, and the rock is again raised and carried down stream, until finally, by repeated liftings and struggles, the ingenious, persevering nest-builder is swept down to the nest, where the load is deposited. This laborious work is carried on until the pile has attained a height of two or three feet, and a diameter of four. No special form seems to be necessary. The nest is generally oval, compact and well devised to contain the eggs, which are carefully deposited within, thus affording protection in its numerous interstices for the young when they hatch. When about six inches long, the young _Petromyzon marinus_, which is a strange little fellow, is devoid of teeth, and blind, and