446 Mr. A. Fraser. On the Development of the [Mar. 30, 



March 30, 1882. 



THE PRESIDENT (followed by THE TREASURER) in tlie Chair. 



The Right Hon. Anthony John Mundella was admitted into the 

 Society. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. " On the Development of the Ossicula Aiiditns in the Higher 

 Mammalia." By Alexander Fraser, M.B., &c, Senior 

 Demonstrator of Anatomy, the Owens College, Manchester. 

 Communicated by Dr. Allex Thomsox, F.R.S. Received 

 March 16, 1882.. 



(Abstract.) 



The paper "begins by -a history of the various views held np to the 

 present date concerning the origin of the Ossicula Auditus. 



The author then describes the methods of preparation, and the 

 results of his own observations made upon complete series of sections 

 from the rat, pig, sheep, dog, rabbit, calf, mouse, and human embryos 

 at different developmental stages. He gives a short anatomical sketch 

 of the parts in connexion with the proximal extremities of the first 

 two post-oral cartilages, including the ganglion, the maxillary and 

 mandibular branches of the fifth nerve, the seventh nerve, and its 

 mandibular (chorda tympani) branch (noting the relation which this 

 branch bears to the hyoidean cartilage, and the long crus of the 

 incus), the auditory vesicle and its capsule with the difference in 

 development between the oval and round fenestrae, the primitive 

 jugular vein, the hyo-mandibular cleft (and its non-perforation in the 

 region of the membrana tympani), and the tympanic annulus. 



The author describes the malleus as having its origin in the 

 proximal extremity of the mandibular cartilage, the apex of which, 

 growing in a ventral direction, depresses the dorsal wall of the 

 meatus auditorius externus upon the ventral, and thus becomes the 

 manubrium of the malleus. He further compares the embryonic ossicula 

 with their form in the adult, and traces the origin from the mandibular 

 cartilage of certain parts in the adult malleus of Mammalia of great 

 morphological significance. 



