No. I.] THE VERTEBRATE EAR. gg 



top of the cell, instead of taking in the whole cap, which latter 

 view Gottstein adopted and figured the hair cells accordingly. 



Retzius (1872, 238) found the cells of the cristse and maculae 

 to be of two sorts, supporting cells and sense cells. The latter 

 are flask-shaped, hair-bearing structures, which carry upon their 

 thickened end plates tufts of hairs, ten to fifteen in number, 

 and not infrequently even a larger number. These may be 

 only the fibrils of a single large hair, and they are found of 

 various lengths in maceration preparations. The auditory cells 

 are directly continuous with the nerve fibres. 



Nuel (1872, 207) gives an account of the tectorial membrane, 

 but as it is reproduced in his later account, it will be given in 

 a succeeding paragraph. 



Boettcher (1872, 36) : In the cat and the dog the Corti's 

 pillars develop during the period shortly before and after birth. 

 The hairs on the upper end of the hair cells are arranged in a 

 curved line, not in a tuft, as Waldeyer thought. 



He defends his views as to the nature of the membrana tec- 

 toria, viz. that the fibres of this plate are connected with the 

 hair cells, and that the hairs of the latter are consequently 

 artifacts. 



In a young hare Boettcher found that the third zone (as Hen- 

 sen found in rabbit) was formed entirely of a perforated mem- 

 brane, which lies on the dorsal surface of the membrana tectoria 

 propria and forms the inner part of the membrane, z.e. third 

 zone. It is a genuine membrana fenestrata, and lies directly 

 upon the cartilaginous spiral ridge. Further outward it lies 

 over the striated portion, and reaches to the processes found 

 on the outer border of the second zone. Adherent to these 

 processes he found in the cat a row of fine fibres at very regu- 

 lar distances from each other, and a second row of similar ones 

 nearer the ventral surface of the membrane. The membrane 

 in hares is much thinner than in cats and dogs, and begins 

 about the middle of the distance between the vestibular wall 

 and the free border of the auditory teeth. The conditions in 

 the rabbit and hare are unlike those in the dog and cat. In 

 these latter there are fibres and outline figures upon the upper 

 surface of the membrane. 



These fibres are, so far as position is concerned, the equiva- 

 lent of the fenestrated membrane of the rabbit. This is not 



