222 PHILOSOPHICAL TRANSACTIONS. [aNNO J 705. 



outermost is only an expansion or continuation of that fine skin that invests 

 the meatus auditorius. He thinks the passing of the smoke of tobacco from 

 the mouth by the ears, the evacuating of pus, &c. from the barrel the same 

 way, seem to evince the necessity of a perforation, or hiatus, in the membrana 

 tympani; though none of his repeated experiments were so successful as to 

 discover it hitherto. 



He reckons the sinuses of the processus mamillares, which are divided into 

 several cavernous cells, as part of the cavity of the barrel, because they com- 

 municate with it: and in some other animals, where these sinuses are wanting, 

 the cavitas tympani is considerably larger. The head of the malleus lies hid in 

 the beginning of the sinus mastoideus, but is no ways connected to it. In its 

 manubrium, or handle, he demonstrates three processes, which he names major, 

 minor and minimus: to the three muscles of the malleus, he gives the same 

 names of its processes to which they are inserted. Musculus processus majoris, 

 first discovered by Eustachius, rises from the cartilaginous part of the tuba 

 Eustachiana, and not from that bony canal which runs laterally upon the osseous 

 part of the same; then running along that canal, it enters the barrel, where 

 its tendon, being infiected a little downwards, is inserted in the processus mal- 

 leoli major. He says, that none have taken notice of the true origin of this 

 muscle before him, notwithstanding its rising from the tube does very much 

 conduce to hearing. Musculus processus minoris, is the laxatorauris externus; 

 he reprehends some modem anatomists for omitting the description of this 

 muscle, though fairly described by J. Casserius long ago. Musculus processus 

 minimi begins at the side of the barrel next the face, and running along the 

 same, it comes to its insertion, being inflected under the chorda tympani, in 

 the smallest process of this bone. 



The incus is joined by small ligaments to the malleus, whence these bones 

 have either no motion at all, or but a very obscure one between themselves. 

 The long leg of the incus runs parallel with the handle of the malleus, the ex- 

 tremity of which is crooked a little downwards: its shorter leg is connected to 

 the side of the sinus mamillaris by a ligament, which yet allows it a small 

 motion. The bone that Sylvius discovered, should be called ovale, from its 

 figure, and not orbiculare, since it is not round. 



The figure of the basis of the stapes is nearly elliptical ; yet its margin is a 

 little defective on one side. It is convex towards the labyrinthi vestibulum, 

 and concave towards its head. Its bony substance is so thin, that it is almost 

 transparent, and not pierced with holes, as a certain modern describes it. The 

 sides or branches of the stapes are furrowed on the inside ; the space between 

 being sometimes shut with a membrane, and often but half shut; but for the 



