THE SENSES. 275 



turn of the cochlea, is covered with three grooves opening below into the canal, 

 fympanicus, and diverging upwards (for the anastomosis of Jacobson). 



c. Eminentia papillaris , the pyramid, a small conical projection behind the 

 fenestra ovalis ; a fine orifice in its apex leads to a canal which passes away 

 under canal. Fallopia, and is connected with it ; this is canalis stapedii. 



d. Fenestra rotunda, s. cochlea, behind the promontory in a depression 

 (which leads to the vestibule'} is closed by a fibrous membrana tympani secun- 

 daria, and leads into the Scala tympani of the Cochlea. 



At the anterior boundary the tympanic cavity contracts and runs 

 out into two canals, the superior of which, canalis tensoris tym- 

 pani (for m. mallei internus) is separated by a thin osseous la- 

 mella from the inferior canal, that is, the osseous tuba Eustachii, 

 and is said to commence as a semi-canal (semicanat.) with a wide 

 open-mouthed lamina, proc. cochlearis. Above and behind the 

 threat opening of the sinus masloideus leads into the cells of proc. 

 mastoideus. These cells are filled with air and covered with Epi- 

 thelium. The superior boundary is vaulted, and the head of the 

 malleus and of incus are situated in it. 



510. 2. The Bones (ossicles) of the Ear, Ossicula auditus. 



These are (three to four) movable osseous pieces, associated at 

 angles into a chain, which are situated from without inwards be- 

 tween the memb. tympani and the fenestra ovalis. 



a. The malleus lies immediately upon the memb. tympani. We observe on 

 it, Head, neck, handle, and two processes. 



1. Head, an oval, smooth enlargement, situated in the superior part of the 

 tympanic cavity, above the memb. tympani, unites on its posterior concave 

 surface with the incus, and is placed upon 



2. The neck, a narrow piece inclined from before outwards, which passes 

 into 



3. The handle (manubrium). This passes off from the neck at an obtuse 

 angle, downwards and forwards, and terminates with a roundish point in 

 the centre of the memb. tympani between the internal and central laminae. 



4. Processus brevis s. obtusus arises at the commencement of the manubrium, 

 on the outer side, and presses the superior part of the membr. tympani 

 (umbo) rather outwards in the ext. auditory meatus. 



5. Processus longus (s. folianus) arises from the anterior part of the neck, 

 long and thin, and enters into the fissura Glaseri, where lig. mallei ante- 

 rius is applied. 



b. The incus, the anvil, like a molar tooth, is situated behind and below 

 the malleus. Its body, that is, the most superior thick piece, has a concave 

 articular surface directed forwards for caput mallei. Its shorter, superior pro- 

 cess passes backwards, and attaches itself to the cells of the proc. mastoideus. 



