A. ÏEKAO : 



transitional stages of lens epithelium cells to photogenous cells. Against 

 the underlying connective tissue, the marginal zone is quite ill-defined, in 

 correlation with the fact that the basement membrane is so thinned out that 

 it is scarcely distinguishable as such in the parts concerned. 



In the photophores preserved by me, I find that not a few of them 

 have the photogenous cells in the process of breaking up. This may be 

 due to the faulty action of the fixing or preserving reagents, or more 

 probably to the fact that the specimens were kept in captivity — therefore, 

 under conditions which may be assumed to have been different from those 

 of their natural habitat — for about ten hours before the fixing took place. 

 The breaking up first commences in some of the cells in the peripheral 

 parts of the photogenous layer ; thence it extends into those more centrally 

 situated, eventually affecting all the photogenous cells in the layer. The 

 first indication of the process consists in the appearance, in the cell body, of 

 a few unusually large granules among the uniformly fine ones before 

 described. Soon the large granules coalesce into a single homogenous and 

 refractive mass. This increases in volume at expense of the original finely 

 granular cell-body and finally completely replaces the latter. After this 

 change, the cell-body exhibits much the same reactions towards staining 

 reagents as before, except that it now becomes stained deep black by 

 Heidenhain's iron-haematoxylin. This indicates that, hand in hand with 

 the physical change, some chemical change has also taken place in the 

 substance of the cell-body. Now, the transformed cell-body begins to 

 undergo disintegration into fragments of various sizes. A number of these 

 fragments are shown in fig. 2. While some are very small and simply 

 granule-like, others are very much larger and present a spherical, ovoid or 

 almost indefinite shape. Frequently they show a constriction or constrictions 

 on the body and thus have a biscuit-like or a lobate or tuberculate-like form. 

 The substance of the fragments is either of a homogeneous appearance or 

 exhibits a varying number of large and small drop-like inclusions. Micro- 

 chemically it behaves just as before the disintegration. 



Sooner or later, the detrital fragments move off from the site of their 



