ORGAN OF CORTI. 157 



pillar consequently covers the caput and the capitular lamina 

 of the external one, but so that the much longer phalangiform 

 extremity of the latter constantly remains free (fig. 326,^ 

 and I ; fig. 329, c and d ; fig. 334, e-^). As the internal pillars 

 are more numerous, and their capita consequently more slender 

 than the outer ones, it follows that the caput of an external 

 pillar always touches at least two internal pillars, and thus the 

 previously mentioned lateral excavations of the inner capita is 

 produced. Owing to this circumstance, the coupling of the 

 pillars to one another is of a very firm character. The dissi- 

 milarity in point of number here leads to the same results as 

 occurs in the ginglymus of the articulation at the elbow ; 

 namely, that the occurrence of any lateral displacement of the 

 pillars is prevented. It" remains, however, an open question 

 whether a radial articular movement of the capitula of the 

 pillars (around a spiral axis) be possible. I have always ob- 

 served that the surfaces in contact with one another are flat ; 

 such a movement, however, could only occur with coincident 

 bending of the pillars, if the attachment of the bases to the 

 membrana basilaris were fixed, as appears to be the case, espe- 

 cially in regard to the external pillars, the bodies of which 

 -often break off, whilst the bases remain adherent. 



If the mode of connection of the capitula with one another 

 be carefully considered, it enables us to understand the some- 

 what complicated markings presented by the vestibular surface 

 of the arches of Corti, when seen en face (figs. 326 and 334. 

 A number of spiral and radial lines then make their appear- 

 ance, of which the spiral are occasioned on the one hand by the 

 internal and external contour lines of the two opposite capitula, 

 and on the other by the external margin of the capitular lamina 

 of the internal pillar (fig. 334), whilst the radial are caused by 

 the contour lines of the capitular laminae of the several inter- 

 nal pillars, and by the capitular masses and the peduncles of the 

 capitular laminae of the external pillars, seen indistinctly shining- 

 through the former. In regard to this point, I must refer the 

 reader to figs. 326 and 334, which may be combined with the 

 vertical sections exhibited in figs. 331 and 332. A few words 

 may still be added in reference to the internal line of demarca- 

 tion of the capitular laminae of the inner pillars. One of these 



