On the auditory ossicles of Rhytina stelleri / by Alban Doran ; (communicated by W.H. Flower).

  • Doran, Alban H. G. (Alban Henry Griffiths), 1849-1927
Date:
[1883]
Catalogue details

Licence: Public Domain Mark

Credit: On the auditory ossicles of Rhytina stelleri / by Alban Doran ; (communicated by W.H. Flower). Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Manatee, and is situated lower down or closer to the foot-plate. This plate is proportionately broader than in Manatus• so (as the appended measurements prove) it is as wide as the widest expanse of the crura. The following measurements (in centimeters) show that Rhy- tina possesses a stapes absolutely larger than that of any other animal. It must be remembered that the ossicula of the Sirenia are bulkier than those of the Cetacea. Vertical Greatest breadth Breadth of measurement. across crura. foot-plate. Rhytina T9 0-9 0-9 Manatus l-(i 0‘8 06 Halicore TO 05 0-6 Balsena mysticetus .... T1 ( Crura expanded regu- j 0-5 Balscnoptera Sibbaldii .. TO j larly to foot-plate. )0-7 Elephas indicus 0-6 04 In conclusion, it may he said that the malleus of Rhytina is larger than in Manatus; and therefore it is the largest and bulkiest malleus to be found in the whole section of the animal kingdom where such a bone exists; that in the characters of its body it resembles Manatus rather than Halicore; and that in the manu- brium it differs from the other Sirenia, and is far more generalized. The incus is of the Manatus type *, and so is the stapes, which is also the largest and bulkiest stapes to be found in any animal. In the appended drawings I have placed the mallei of Rhytina and Manatus in the position best adapted for showing the differ- ences in the manubrium. A. Malleus of Rhytina Stellcri. B. Malleus of Manatus americanus. Both natural size and outer aspects. C. Stapes of Rhytina, natural size. The lettering applies as follows :—a.s. articular surface ; p.h. processus brevis; p.g. processus gracilis ; e.m.n. external surface of manubrium. * The body of this bone is bulkier in Macrorhinus than in Rhytina ; but the crura are slender as in other allied Seals. Hence Rhytina exceeds every living animal in the size of all its ossicula.
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