AND THE CRISTA SPIRALIS OF THE COCHLEA. 65 



epithelial ridge and even of the crista spiralis. This property may result in further 

 alterations. At certain places the bars show a tendency to split longitudinally 

 into two parallel lines, the clear space between which is bridged across, as in the 

 case of so many intercellular spaces between epithelial cells. According to N. 

 Van der Stricht (1908), this process of longitudinal splitting of the bars occurs 

 regularly in the course of development of the membrana reticularis covering the 

 crista and macula acusticse. It also takes place during the formation of the mem- 

 brana limitans olfactoria (1909). The power of extension of the bars over the 

 apices of neighboring cells I will discuss in a later chapter. 



The superficial epithelial mosaic of the cochlear duct has been described by 

 Lavdowsky (1876) and Retzius (1884). Both investigators used silver nitrate as 

 a fixing agent and thus stained the intercellular cement black. Vernieuwe (1905), 

 after staining the terminal bars intensively blue by iron hematoxylin, first rec- 

 ognized the true nature of these elements and their special chemical composition. 

 He observed the indifferent mosaic of the greater ridge, and since the number of 

 fields and the number of nuclei deeply situated are approximately the same, he 

 concluded that all the cells reach the surface, and consequently that this thick 

 epithelium ought to be considered as a simple columnar epithelium. In 1902 the 

 terminal bars on the surface of the adult organ of Corti had already been described 

 by Held; in 1908 N. Van der Stricht and in 1909 Held studied them in the embry- 

 onic and adult cochlea on the surface of the indifferent and sensorial epithelium. 



CRISTA SPIRALIS, LIMBUS SPIRALIS. HABENULA DENTATA. HABENULA SULCATA. 



Former authors, including Huschke (1832) and Corti (1851), mention the 

 existence of two regions in the surface of the crista spiralis. One, lateral the zona 

 dentata or sulcata, near the vestibular lip of the sulcus spiralis displays a series 

 of elongated protuberances more or less parallel the teeth of Huschke, separated 

 by furrows within which Corti had previously noted vestiges of nuclei. Another 

 region, axial, near the attachment of Reissner's membrane, exhibits prominent 

 "warts," "swellings," or papillae, and may be termed the zona papillaris. 



The crista is formed by connective tissue which was regarded by Hensen (1871) 

 as cartilaginous, or as intermediary between cartilage and connective tissue. Gott- 

 stein (1870) and Waldeyer (1872) considered it, likewise the teeth, as osteoid 

 substance and calcified. Hensen (1863) and Kolliker (1867) described the teeth 

 as a product between and derived from the superficial epithelial cells, but Boettcher 

 (1869), Waldeyer (1872), Denis (1901), and Vernieuwe (1905) among others, demon- 

 strated that they are formed by a proliferation of the subjacent connective tissue 

 between these elements. What becomes of these epithelial cells during and after 

 this proliferation? Boettcher (1869) and V. Winiwarter (1870) noticed rows of 

 nuclei without cytoplasm within the furrows separating the teeth, and Winiwarter 

 described a kind of superficial mosaic without nuclei. He stated it in the following 

 terms: "Sehr eigenthlimlich ist die auf der oberen Flache des Gehohrwulstes mit 

 starkeren Vergrosserungen wahrnehmbare Epithel-Zeichnung, hervorgebracht durch 

 feine, scharf ausgedriickte Contouren ohne Spur von Kernen. " It is, of course, 



