enlarged, their greatest diameter being 4 twelfths. The liver is large, the right lobe being 3-1/2 inches long, the left 2-1/2. The trachea, _m_, is 7-1/2 inches long, of moderate diameter, the rings roundish and ossified, about 140 in number, its breadth at the top 4-1/2 twelfths, gradually diminishing to 3 twelfths. At the lower part several of the rings are united so as to form an irregular dilatation, bulging out into a rounded sac, _n_, on the left side, its greatest diameter being 10 twelfths. The bronchi are of moderate length, wide, with about 25 half rings. The contractor muscles are rather strong; and besides the sterno-tracheals, _o_, _p_, there is a pair of cleido-tracheals. In a female, the gizzard is 2 inches in its greatest diameter; the intestine is 5 feet 2 inches long. The contents of the œsophagus and stomach as in the male. BLACK-THROATED DIVER. _COLYMBUS ARCTICUS_, LINN. PLATE CCCXLVI. MALE, FEMALE, AND YOUNG. One of the most remarkable circumstances relative to this beautiful bird, which is intermediate between the Red-throated Diver and the Loon, is the extraordinary extent to which the wanderings of the young are carried in autumn and winter. It breeds in the remote regions of the north, from which many of the old birds, it would seem, do not remove far, while the young, as soon as they are able to travel, take to wing and disperse, spreading not only over the greater part of the United States, but beyond their south-western limits. In the Texas I saw individuals of this species as late as the middle of April 1837; and I find it enumerated in a list of the birds observed by my young friend Dr J. K. TOWNSEND on the Columbia River, where he also met with _Columbus glacialis_. Its ramblings over a considerable portion of northern and eastern Europe have equally been noted, and it has been found breeding in the extreme north of Scotland. For many years I knew the young of this bird only by the name “Imber Diver,” applied by BEWICK to that of another species, and now have pleasure in looking upon a drawing of mine, made about thirty years ago, with that appellation attached to it. Very few old birds in full plumage have been procured within the limits of the United States, and none in as far as I know, farther south than the Capes of Delaware. No sooner has the foliage of the trees that border our western waters begun to drop and float on the gentle current of the fair Ohio, than the Black-throated Diver makes its appearance there, moving slowly with the stream. The Mississippi, Missouri, and their tributaries, are at the same period supplied with these birds. Along our eastern and southern shores they are seen from the end of autumn until spring.