"Till a comparatively recent date it was not certainly known that eels have eggs which develop outside of the body. Even now the breeding habits are scarcely known, but it is supposed that the spawning takes place late in the fall or during the winter, near the mouth of rivers, on muddy bottoms." (Bean.) December Fourteenth The so-called glass snake is truly speaking not a snake, but a legless lizard. It forms part of the food of the true snakes. Its body is very brittle, a light blow with a stick being sufficient to break it in two. Although it is true that another tail will grow (provided not more than a fourth of the body is missing), it is not true that the broken pieces will eventually unite, or that a head and body will grow on the tail piece. December Fifteenth How often you read of, or heard some one speak of, the whale as "the largest of fish." A whale is a _mammal_, because it suckles its young. It is not only the largest of _living_ mammals, but, according to Mr. Lucas, the large ones are larger than any of the enormous reptiles that inhabited the world before the advent of man, and whose fossil remains may be seen in any of our large museums. Notes December Sixteenth The quiet little tree sparrows spend the winter with us feeding on the seeds of weeds and grasses. You will find their tracks in the snow where flocks have been eating ragweed seeds, and you are likely to see some of them fluttering about in the bushes along the river banks, or in the frozen swamps uttering a pleasing call note. They can be identified by the distinct black spot on the breast and their pinkish bills. December Seventeenth There is no better time to study the tracks and nightly doings of animals than after the first fall of snow. Start early in the morning and see how many stories the tracks have written. December Eighteenth Following the tracks of a white-footed mouse in the woods, they lead you to a hollow log, at the entrance of which are a number of beech-nut shells, remains of a midnight feast taken from a winter store-house. From here the mouse went into the field, and then the tracks stop abruptly, leaving you to guess the rest. Possibly one of the several species of owls that inhabit your locality could explain the sudden ending of the trail. Notes December Nineteenth Continuing through the woods, you soon discover the trail of two birds whose feet are not quite the size of those of bantam chickens. Following them a few hundred yards you come to a bedded spot in the snow, beneath the drooping branches of a spruce. Not far from here, two ruffed grouse rise, with a loud whirr of wings, and speed off before your startled eyes. These are the birds whose tracks you have been following. December Twentieth