284 LAMINA SPIRALIS OF THE COCHLEA. 



over the groove of Huschke. Some of the columns divide, 

 others unite together, as they pass outwards to form these 

 teeth ; which are termed " teeth of the first series." In the 

 grooves between the columns are numerous nuclei, which 

 resist acetic acid, while the former swell up, and become 

 somewhat striated under its action. 



The habenula denticulata consists of a series of apparently 

 jointed rods, laid on the surface of the membranous portion 

 of the so-called lamina spiralis ; each rod in the series lying 

 in the direction of the radius of the cochlea. The first or 

 inner segments of these rods form a series of compressed 

 laminae, attached across the bottom of Huschke's spiral 

 groove, with narrow chinks between them, which are, in fact, 

 the orifices through which the cochlear nerve-filaments pass, 

 as already stated. These central segments are the "dents 

 apparents " of Corti. The second segment, or portion of each 

 rod, is also compressed, and lies flat on the membranous 

 spiral lamina, and is loose and movable, except at its inner 

 end, where it presents an enlargement like a nucleus, which 

 was supposed by Corti to be the joint by means of which the 

 rod is attached to and moves on the membrane ; but which 

 Kolliker has discovered to be the point at which one or more 

 of the ultimate filaments of the cochlear nerves become 

 connected with the rod, after they have passed through the 

 orifices already mentioned. The series formed by these 

 second segments of the rods are the so-called " teeth of the 

 second order." The terminal segment is connected with the 

 second by means of two short quadrilateral segments, the 

 " coins articulaires " of Corti. The terminal segment is elon- 

 gated and compressed. To its upper surface three pyriform 

 bodies, each of which contains a nucleus, are attached by 

 short peduncles, so as to be laid over one another, from 

 within outwards. Corti and Kolliker describe the outer 

 extremity of this segment as somewhat expanded and forked, 



