STUDIES ON CILIATED CELLS 231 



1) In the first type, such as in efferent tubules of the testis 

 of Reptilia and mammals, I have never been able to recognize 

 any well-defined cuticle; what can be seen is an ill-defined crust, 

 in which the basal corpuscles He, thus giving rise to the appear- 

 ance of a longitudinal striated cuticular border. That this ap- 

 pearance is owing to the existence of basal bodies in the crust, is 

 readily explained by the study of cihogenesis in epididymis cells 

 of mammals. In efferent tubules of the mouse, as will be after- 

 wards described, it is evident that cells with brush borders, which 

 are provided with a crust on their distal margin (fig. 89), become 

 converted into ciliated cells, and that from the way that the 

 newly-formed basal corpuscles arrange themselves in the crust. 

 In one word, the striated cuticle in this case is nothing but a 

 portion of the crust defined by the arrangement of basal bodies. 



2) To the second type belong the ciliated cells of the epi- 

 thelium of the pharynx and tela of Amphibian larvae. As the 

 representative of this group I take the ciliated cells of the epi- 

 dermis, the most closely examined. As will be afterwards de- 

 scribed, these ciliated cells are developed from non-cihated, the 

 cuticle of the latter becoming directly converted into that of the 

 former. The cuticle, in profile longitudinally striated, exhibits, 

 in surface view, a well-marked reticular appearance. If these 

 two features are considered associated with each other, it becomes 

 evident that the cuticle is composed of closely apposed aloeoli, 

 the junction of the alveolar walls appearing, in side view, as 

 striae (compare: F. E. Schulze '69, '88; 0. Schatze '07; S. Saguchi 

 '15), through which the cilia pass into the cytoplasm. 



The structure of the cuticle of ciliated ependyma cells is the 

 same as that above described, except that the longitudinal striae 

 are very closely applied, rendering close examination extremely 

 difficult (figs. 36, 38). Studnicka ('99) describes the cuticle of 

 ciHated cells in the tela epithelium of Petromyzon as provided 

 with small canals through which the cilia pass into the interior 

 of the cell. This seems, however to me to be an artificial result 

 brought about by the fixation; for but one of the seven cells 

 in his figure 5 has such canaliculi, and he says in his text that 

 '^sie (canaliculi) sind, wie es scheint, viel grosser als es zu diesem 

 Zweck (passing through of the cilia) notig ware " 



