478 



IRVING HARDESTY 



form. It is seen that its vibratory portion or outspanning zone 

 (OZ, this figure and figure 2) increases gradually and regularly 

 in width from its basal end (BE) to its apical end. Measure- 

 ments of its width in its different turns recorded in my paper of 

 1915, show that this zone is about 7 times as wide in the apical 

 as in the basal end. The ends terminate bluntly rounded. Lib- 

 eral measurements of the width of the basilar membrane (the 

 portion of the membranous spiral lamina supposed to vibrate) 

 show that its apical end is only about 1.8 times wider in the 

 human and averages 1.4 times wider in the hog than its basal 

 end. Measurements of the attached axial zone of the tectorial 



EXPLANATION OF FIGURES 



REFERENCE LETTERS 



AM, 'Accessory membrane' 

 AS, Adjusting screw 

 AZ, Attached axial zone 



B, Battery 

 BE, Basal end 



BL, Bony spiral lamina 

 BW, Bony wall of cochlea 

 BM, Basilar membrane 

 BS, Basis of stapes 



C, Cork 



CD, Cochlear duct 



CN, Cochlear nerve 



CP, Copper plate 



CW, Copper wire 



ED, Endolymphatic duct 



EM, External auditory meatus 



FC, Fenestra cochleae (rotunda) 



FV, Fenestra vestibuli (ovalis) 



GP, Glass plate 



GT, Glass tube 



H, Horn 



HT, Huschke's teeth (edge of vestib- 

 ular lip of spiral limbus) 



L, Boundary line between outspanning 

 and attached axial zone. (Line of 

 imprint of Huschke's teeth) 



.1/, ^lanubriuni oi Malleus 



MB, Metal Japan button 



0, Auditory ossicles 



OZ, Outspanning zone of tectorial 



membrane 

 PW, Platinum wire 

 R, India rubber to make water-tight 

 RC, Cover for organ reed 

 RT, Rubber tube 

 S, Switch 

 SS, Spiral sulcus 

 SC, Set screws 

 SG, Spiral ganglion 

 SL, Spiral lamina (basilar membrane) 

 <S Lg, Spiral ligament 

 SM, Signal marker 

 ST, Scala tympani 

 SV, Scala vestibuli 

 TL, Tympanic lip of spiral limbus 

 TM, Tectorial membrane 

 TpM, Tympanic membrane 

 WB, Heavy wooden block 

 WS, Wooden strip 

 VM, Vestibular (Reissner's membrane) 



