Prof. DeaD C. Worcester has effected a revolution in the methods of the university museum. It cousists in making groups of birds, so that important facts concerning their habits and life history may be fnlly set before the spectator. As the visitor enters thes outh hall of the second story his attention is arrested by a thick false wall, in which is placed a box witb a glass front. It contains th8 nest of a marsh hawk, with the female bird jnst preparing to enter, and the male bird perched on an old stuinp among the decayed roots of which the nest is placed. Shrubbery stands tbickly about, freshly budded, the young leaves just beginning to give spring freshness to the scène, while long grass blades thinly push themselves up through the dead grass of a past year and aniong a litter of smali sticks and brush. That nest was found by Mr. Worcester exactly as it lies in the museum case. He brought in with him not ouly the nest, but the decayed stump, the shrnbbery, the ground under the nest with all its litter upon it, and his assistant made ruolds of the leaves and grasses, so that the was leaves and was grass blades now standing in the . case are exact reprodactions of the 1 ishable part of the scène as it originally existed. It took many an hour of watching and patience to capture the whole outfit; but Mr. Worcester will lie in wait 10, 15, 2 hours, if necessary, in order to get the parts that really go together for one of these groiips. At the south nd of the same hall stands a doublé group . The section of an oak tree carries the nest of a redshouldered hawk, with the handsome j pair of bfrds that constrncted it. The nest is crowded with eggs. On the ground is a male whip-poor-will, with his mouth wide open, strutting upon a decayed lichen-streaked litnb fallen írom some tree. Near by is the nest, in a flurry of brown oak leaves. The feniale whippoor-will sits quietly in the dried leaves, close by the lichenstreaked limb, and her colors and ruarkings are identical with those of leaf, bark and lichen, so that ordinary observation will not lócate her. A more perfect illustration of protèctive rnirnicry in pluinage conld not be given. Ülany snch groups are in preparation. There will be hundreds of them before the work is done that is marked out. Now several woodpeckers, warblers, a rail aud young chick-a-dee, bitteru and others are being arranged. The labels upon the museum cases are very carefully made to be plain to uuscientific people. The scientific name-i are there, but so are the popular narue, aud explanations are made iu plain Euglish, without soientific frills.