Our next subject is named The Ornithorhynchus Paradoxus, and is a very singular quadruped, remarkable for its structure. The head is similar to that of a duck, which would lead to the supposition that it belonged to an aquatic bird. Both jaws are as broad and low as those in a duck, and the calvaria has no traces of a suture, as is generally the case in full-grown birds. In the cavity of the skull there is a considerably bony falx, which is situated along the middle of the os frontis, and the ossa bregmatis. The mandible of this animal consists of a beak, the under part of which has its margin indented as in ducks, and of the proper instrument for chewing that is situated behind within the cheeks. Dr. Shaw says it has no teeth, though Mr. Home found, in a specimen examined by him, two small and flat molar teeth on each side of the jaws. The fore part of this mandible, or beak, is covered and bordered with a coriaceous skin, in which three parts are to be distinguished, within the proper integument of the beak. Into these three parts of that membrane numerous nerves are distributed, intended, probably, as the organs of feeling, a sense which, besides men, few mammalia enjoy ; that is, few animals possess the faculty of distinguishing the form of external objects and their qualities, by organs destined for that purpose, - a property very different from the common feeling, by which every animal is able to perceive the temperature and presence of sensible objects, but with-out being informed, by the touch, of their peculiar qualities. Thus the skin in the wings of the bat, and its ear, are supposed the organs of common feeling, by means of which they are enabled to flutter, after being blinded, without flying against any thing. The whiskers of many animals appeal likewise to serve the same purpose of informing them of the presence of sensible bodies, and hence they have been compared to the antennae of insects.

But to return to the ornithorhynchus : It is an animal which from the similarity of its abode, and the manner of searching for food, agrees much with the duck, on which account it has been provided with an organ for touching, viz. with the integument of the beak, richly endowed with nerves. This instance of analogy in the structure of a singular organ of sense in two species of animals, from classes quite different, is a most curious circumstance in comparative physiology, and hence the ornithorhynchus is looked upon as one of the most remarkable phenomena in zoology.

The Ornithorhynchus Paradoxus.