THE FUNCTION OF NETTLECELLS. 395 



whether the cnidoblast was in connection with the nervous 

 system described particularly by the brothers Hertwig, Such 

 a connection has been demonstrated in many cases by Jickeli, 

 the author, and Korotneff. 



In the lower strata — subepithelium — of the dermis, ganglion 

 cells are met with in those parts generally where cnidoblasts are 

 situated. These ganglia cells are multipolar. Their processes 

 are connected with slender nerve-fibres extending tangentially 

 between the mesodermal jelly (the supporting membrane, 

 Stiitzlamelle) and the outer epithelium. Some of these pro- 

 cesses, however, extend in a radial, centrifugal direction, and 

 these are connected with the large cnidoblasts. No con- 

 nection has hitherto been observed with sufficient certainty 

 between the ganglion cells and the small cnidoblasts. 



The protoplasmatic outer portion of the cnidoblast is pro- 

 longed into a process extending centripetally like a peduncle. 

 This is composed of granular protoplasm and forms the 

 connection between the cnidoblast and the ganglion cell below. 

 Hamann found that these peduncles, in some cases at least, were 

 not formed of granular protoplasm, but appeared as transparent 

 and structureless peduncles formed of the same substance 

 as the supporting mesodermal membrane. Subsequently I was 

 able to demonstrate that the large cnidoblasts have two pedun- 

 cles, one a transparent supporting rod as described by Hamann, 

 and one a granular thread, which connects it with the ganglia 

 cells of the subepithelium. Whilst the former is always quite 

 straight, the latter generally appears more or less curved and 

 irregular. 



These cnidoblasts are surrounded by high and slender cylin- 

 drical ciliated cells which form the outermost layer, or they 

 penetrate the large cells of the outer epithelium. In those parts 

 where the epithelium is formed by flat and low pavement cells, 

 large cnidoblasts are never observed. 



The small cnidoblasts, however, are scattered over the surface 

 more indiscriminately and occur in great abundance also in the 

 pavement cell areas. In these areas a subepithelial layer of 

 ganglion cells seems not to occur. 



