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XVIII. Morphology of the Mammalian Ossicula auditus. By Alban H. G. Doran, 

 F.B.C.S. (Communicated by Professor Flower, F.B.S., F.L.S., 8fc.) 



(Plates LVIIL-LXIV.) 



Eead December 21st, 1876. 



AMONG John Hunter's original collection are some preparations in spirit, repre- 

 senting the tympanic region of mammals, with the small ear-hones in situ, hut only a 

 very few imperfect dry specimens of the internal ear-bones themselves, though those of 

 man are better represented. Little was added to this department at the Poyal College 

 of Surgeons' Museum until 1866, when Mr. Toynbee's valuable pathological auditory col- 

 lection showed the want of a corresponding series in the physiological department. For- 

 tunately, about the above date, the nucleus of such a collection offered in that of Dr. Max 

 Hiibrich, of Munich, which the College authorities purchased. The Conservator, Prof. 

 Flower, wisely availed himself of opportunities to increase this ; and at the present date 

 a very complete series of most of the genera of Mammalia is the result. 



In drawing out a catalogue of these, I was led to study minutely and compare the 

 various groups one with the other. I soon found that, excepting the labours of Prof. 

 Hyrtl, of Vienna, on the osteology of the entire auditory apparatus in the Mammalia 

 (' Vergleich. Anat., Untersuch. uber das innere Gehororgan des Menschen und der 

 Saugethiere,' Prague, 1845), little or nothing in a connected form had been done to 

 elucidate the characters of the small ear-bones of Mammalia. Occasional desultory 

 remarks are to be found scattered in papers on human and comparative anatomy ; but 

 these in most cases are entirely lost sight of. This suggested to me, in preparing and 

 arranging the Museum series, to take notes thereon and the critical comparison of 

 the objects themselves and collation of the literature on the subject, have resulted in the 

 following descriptive and comparative account of the ossicula auditus in the class 

 Mammalia. 



In such small objects as the internal ear-bones it is at first difficult to apprehend the 

 value that may be attached to them as regards physiological influence on audition, and 

 still less as to their morphological importance; but if, for instance, those of man be 

 compared with those of marsupials, the wide difference is at once apparent. Again, in 

 such groups as the Carnivora or Cetacea, the family characters derived from these 

 diminutive ossicula are in the main very distinctive. 



As the small ear-bones of the human being, for various apparent reasons, have neces- 

 sarily had most attention called to them, and moreover as man, in other respects, is con- 

 sidered by some a standard of comparison, I have consequently taken the human ossicula 

 first into consideration. Moreover I have described their peculiarities in such a way 

 that the homologies of the parts of each ossicle in the lower mammals may be more 

 clearly understood. 



