304 



GEORGE L. STREETER 



out. Tluil portion of the cocliloar duct that is to foiin the organ 

 of Corti can be recognized by the characteristic form and groiii> 

 ing of its cells. A portion of the main cavity of the scala tym- 

 pani is indicated and to the I'ight of this ai'e a few enlarged retic- 

 ular spaces that are uniting with each other subjacent to the 

 organ of Corti and the basilar membrane. These will in the 

 end become part of the main space. They are here just in the 





SCALA VESTIB. 



vVi^'-'-'^A SCALA TYMP. ,.'•■" ■•■7'^'T "^'■^' 







Fig. 1 Section through the second turn of the cochlea in a human fetus 

 130 mm. CR length (Carnegie Collection, No. 1018). Enlarged 60 diameters. 

 This section shows the topography of the cochlear duct and the general char- 

 acter of the periotic spaces that are developing along its inner margin. De- 

 tails of this same section as seen under higher magnification are shown in figures 

 2 and 3. 



process of coalescence, the histological features of which pro- 

 cedure are well illustrated in this figure. The trabeculae are 

 stretched out in long strands and in many cases are detached 

 and project into the spaces as free ends. The detached trabe- 

 culae are seen in different degrees of retraction as their con- 

 stituent protoplasm reshapes itself in adaptation to the new 

 boundaries. It is only at the margins of the larger spaces that 

 the cell-processes exhibit the characteristic flattened appearance, 



