In the center of the hall stands a remarkably perfect skeleton of a mastodon, the huge prehistoric elephant that once roamed over Europe and North America. This specimen was found in a peaty swamp near Newburgh, New York, in 1879. Compared with the bony framework of Jumbo on the floor below—the two monsters were separated, perhaps, in order to prevent jealousy between them—the mastodon is shorter in stature, but considerably longer. He stands 8 feet 5 inches from the ground, while his length “over all” is 18 feet, and his immense curved tusks measure 7 feet 5 inches. Near the entrance there is the skeleton of a moa, the great extinct ostrich of New Zealand, and at the further end of the hall that of another animal that existed in the dawn of man’s history—the great Irish elk, found in a peat bog near Limerick. The raised map of New Hampshire, which stands in an alcove on the left hand side of the entrance, is the product of an immensity of care and labor. It is constructed to a scale of a mile to the inch, the elevation being exaggerated about five times, or to a scale of a thousand feet to the inch. It is a good illustration of the value of this sort of map in giving a graphic and comprehensive idea of the topographical and geological formation of a country. [Illustration: A SCREECH OWL FAMILY.] On the wall on the other end of the hall are two large tablets of triassic rock from Massachusetts, showing the foot prints—or “au-toe-graphs,” as James Russell Lowell once ventured to call them—of some huge reptile, and of tiny insects and shellfish. Throughout his inspection of the museum’s contents, the visitor will have noticed that every inch of available space has been occupied, and that the exhibits are in some cases cramped for lack of room. The opening of the new building will effectually remedy this, and provide ample accommodations for the collections and their probable augmentation for some time to come. Its halls are now being fitted up with cases. Its appearance is imposing, and not devoid of a solid and substantial style of architectural beauty. Its general character is Romanesque. The front, which faces Seventy Seventh Street, is of a rough, light reddish stone, with a lofty and rather heavy looking roof of red tiles. It is approached by two wide flights of stone steps, connected with a spacious arched portico by a bridge that passes over a basement entrance below—a very convenient and symmetrical arrangement. Like the older building, the newly finished structure has unusually ample window light, and is altogether well adapted to the purpose for which it is designed. [Illustration] NO BARGAIN.