596 
Proceedings of the Royal Society of Edinburgh. [Sess. 
first arch, also lies slightly dorsal to the first pharyngeal pouch. Again,, 
the stapes is clearly in the area between the fifth and seventh nerves. It 
would appear from the model that the stapes were between the large 
superficial petrosal branch of the seventh and the main trunk which bends 
around the hyoid. But by reference to fig. 11 the stapes will be seen to 
lie between the facial nerve and the trigeminal ganglion just as truly as 
does the incus. Moreover, the stapes is connected to the incus very closely > 
as is shown in fig. 10. 
In view of the evidence submitted I consider it to be clear that — 
1. The whole ossicular chain is developed from the first visceral arch. 
s> C.L 
Fig. 4. — A.C. , auditory capsule ; C.L., crus longum incudis ; G.I., gill 
furrow; C.B. , crus breve incudis; H., hyoid; M., Meckel’s 
cartilage ; Ma., malleus ; P.P., pharyngeal pouch. 
2. That the malleus alone is related to the first visceral bar. 
These relations are shown in text fig*. 4. 
III. 
There remains to discuss the possible homologies of the auditory ossicles. 
Reichert’s view that the malleus is the liomologue of the articulare and 
the incus of the quadrate, so admirably fills all the conditions of an exact 
homology that one is tempted to let the discussion end there. But clearly 
the articulare can be but a portion of the malleus, owing to the fact that 
the former is a covering bone and the latter is not so entirely. With 
this view the majority of authors substantially agree, as Parker (II.), 
Gradenigo, Gengenbaur, Salensky, Hertwig, Kingsley, Wiedersheim, Dollo, 
