The ZOETROPE for imparting apparent motion to these figures consists of a card-board cylinder, A—black on the exterior—12 inches in diameter, and about 8 inches in depth, with 13 equal distant slots b, b, b, near the top, each about 14 of an inch wide and 3 or 4 inches long. The lower end of the cylinder is attached to a disc of wood, c, with a small tube, d, chocked at the top and forming a bearing for a vertical shaft, e, fastened to a platform, f; this forms a support and axis to the cylinder which is caused to revolve either by the motion of the hand, or by a crank handle, g, and a horizontal shaft, h. A fixed wheel, i, is attached to the horizontal shaft on one side of the support, j, and a friction wheel, k, on the other side. A hand of figures; i, i, k, is arranged around the inner circumference of the cylinder and looked at through the slots while the instrument is revolving.

The reproductions of the photographs are published in their present form with the object of disseminating a knowledge of the true positions assumed by animals while performing various movements, and correcting the erroneous ideas almost universally prevailing on the subject; it was not therefore considered desirable to alter the features of the original photographs by retouching or improving the copies.

Being intended for popular use and adapted to the requirements of the ordinary Zoetrope to be obtained at the toy shops, these reproductions are necessarily restricted in the advantages which they may offer for scientific or artistic purposes.

For a more complete investigation of the "Attitudes of Animals in Motion" attention is directed to the ORIGINAL PHOTOGRAPHS now preparing for publication; and for their synthesis to the ZOOPRAXISCOPE invented by the author.