VOL. XXIV.] PHILOSOPHICAL TRANSACTIONS. 225 



has described it, since his happy industry has led him to the discovery of 

 several parts in the ear, &c. which are not to be found in any book extant. 



He says the musculus chondroglossus, described by a certain modern, is not 

 always to be found. The artery that furnishes this cavity with blood, goes off 

 from the carotid, while in its oblique canal in the os petrosum: and the vein 

 that carries back the refluent blood, opens into the diverticulum of the jugular 

 vein : he thinks it may have lymphatics as well as the external cavity of 

 the ear. 



He reckons the chorda tympani to be a twig of the portio dura. He says, 

 that there are 12 orifices that open into the vestibulum, viz. the fenestra ovalis, 

 the 5 orifices of the semicircular canals, one of the canals of the cochlea, and 5 

 holes that admit so many twigs of the portio mollis nervi auditorii. 



He distinguishes the semicircular canals into the major, minor or minimus. 

 He is very nice in adjusting the different lengths of these canals, and the pro- 

 portions they bear to one another in their diameters ; which are different in 

 different subjects, but always alike in both ears of the same subject. 



The cochlea consists of a modiolus or cone, and a septum, which divides it 

 into two canals, which he calls scalae ; that which respects the fenestra rotunda, 

 is the scala tympani or superior; the other, which communicates with the ves- 

 tibulum, he calls the vestibuli scala: he is also very curious in ascertaining the 

 difference between the two scalae: he remarks that modern anatomists have 

 erred in the position of these scalae or turnings; for what they call the superior 

 he rightly names the inferior, et e contr^. Its septum is made up of two sub- 

 stances, one hard, but very friable, called lamina spiralis; the other soft, thin 

 and pellucid, which he calls by a new name, zona cochleae. 



The canal, by which the auditory nerves enter, he divides into the common, 

 which admits both the soft and hard pair together, and the particular, which 

 contains only the portio dura : he observes that it is this particular canal in 

 which the hard portion lies, that Fallopius first discovered, and named it ob 

 similitudinera aquaeductus: the tuba Eustachii is very falsely, though now com- 

 monly so called. 



He observes, that as the portio dura turns aside from the common channel 

 into its own, it detaches one branch, which, going out at a hole in the inside 

 of the OS petrosum, spreads itself on the dura mater and trunk of the 6th pair 

 of nerves, in several small twigs. 



In the bottom of the common canal, he takes notice of 3 small sinuosities 

 or cavities : one descends towards the centre of the cochlea, in which are 

 several holes for the entry of part of the portio mollis, where it is dilated into 

 a very fine membrane, which makes the zona cochleae ; the second goes towards 



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