the thread is semi-fluid, but by exposure it solidifies; and hence contracts and binds the substances forming the nest so closely together, that it is able to withstand the violence of the sea, and may be thrown carelessly about without derangement. In the centre are deposited the ova, very similar to the masses of frog-spawn in ditches.…
"It is not necessary to enter into minute particulars of the development of the young, any further than to add that they were the subject of observation till they became excluded from the egg, and that they belonged to the Fifteen-spined Stickleback (Gasterosteus spinachia). Some of these nests are formed in pools, and are, consequently, always in water: others are frequently to be found between tide-marks, in situations where they hang dry for several hours in the day; but whether in the water or liable to hang dry, they are always carefully watched by the adult animal: on one occasion, I repeatedly visited one every day for three weeks, and invariably found it guarded. The old fish would examine it on all sides, and then retire for a short time, but soon returned to renew the examination. On several occasions I laid the eggs bare, by removing a portion of the nest; but when this was discovered, great exertions were instantly made to re-cover them. By the mouth of the fish the edges of the opening were again drawn together, and other portions torn from their attachments and brought over the orifice, till the ova were again hid from view: and as great force was sometimes necessary to effect this, the fish would thrust its snout into the nest as far as the eyes, and then jerk back-
