472 J. DUESBEKG 



The epidermic ceFs of the superficial layer (fig. 2a) contain a 

 large number of chondriosomes, most of which are long, curved 

 filaments, exhibiting a distinct tendency to run parallel to each 

 other, or the surface of the cell or of the nucleus. Such a dis- 

 position is of course especially conspicuous in a surface-view of 

 the epiderm. Chondriosomes are not so abundant in the cells 

 of the deeper layer. Quite remarkable are some large cells 

 which I suppose to be the glandular cells of the epiderm, though 

 I never saw any indication of a secretion in them. These cells 

 have already appeared during the second day, in Fundulus, and 

 apparently differentiate from cells of the deeper layer. Up to 

 the ninth day, there are found almost exclusively in the ab- 

 dominal wall, near the point of reflection of the epiderm on the 

 yolk-sac, and likewise on the yolk-sac itself in the same neigh- 

 borhood. The groundmass of the protoplasm hardly stains and 

 includes within it an enormous number of long chondrioconts. 

 This appearance I cannot help comparing to that of a bunch of 

 hair, tied together at the top of the cell and 'then spreading out 

 through the whole cell-body. The nucleus floats somewhere in 

 the deeper or middle part of the cell between the chondrioconts 

 (fig. 2b). 



Chondriosomes are also present in the cells of the lens. 



In the central nervous system, each cell contains a few long 

 filaments, running parallel to its long axis, and in addition to 

 these, there occur shorter elements, usually in the shape of loops 

 or circles, at the poles of the nucleus (fig. 1). As in many epi- 

 thelia, the basal part of the cells which reach the basement- 

 membrane contains usually an accumiulation of chondriosomes; 

 this accumulation is visible with low power and defines sharply 

 the outlines of the organ. In ganglion-cells, the chondriosomes, 

 as in the chick-embryo (cf. Duesberg, '10, 2, fig. 6) are short and 

 thin threads, located at one pole of the nucleus. 



The cells of the chorda in young embryos have long chondrio- 

 conts (fig. 1). Later, I find granules, but I am unable to ascer- 

 tain whether this deeply situated organ was well fixed. 



In mesenchyme-cells, chondrioconts are predominant (gran- 

 ules represent most probably the cross-section of filaments). 



