NOTES ON TUE PHOTOPHORES OF SERGESTES PREHENS1LIS BATE. 3 1 I 



origin, without doubt carried on by the blood. So that, after the dis- 

 integration of the cells has advanced to a certain extent, the identical 

 fragments as those found in the photogenous layer begin to be met with 



also in the connective tissue adjacent to the 

 photophore. When all the photogenous cells 

 in a photophore have broken up and the detrital 

 fragments have been deported, the site of the 

 photogenous layer may appear like an empty 

 space, traversed by the connective strands 

 only. I have dwelt at length on the dis- 

 integration of photogenous cells and its pro- 

 ducts, because the matter may have important 

 bearing on the correct interpretation of 

 structural parts observed in preparation of pre- 

 served photophores. Thus, it seems to me 

 not unlikely that what Kemp has given as 

 photogenous cells in his representation of the 

 photophore of Acanthephyra dcbilis (op. cit., pl. LIL, fig. 1, and pl. LIV., 

 fig. 1), are not cells at all, but empty spaces left behind by photogenous 

 cells which had disappeared. The lines taken by him for the wall of 

 photogenous cells were probably nothing else than connective strands, 

 while the mass of minute and highly refractive granules at the end of the 

 nerve-bundle reaching the photogenous layer, may simply be the remnants 

 of the disintegration products of the photogenous cells. 



A few more words concerning the detrital fragments of photogenous 

 cells in „S". prehcnsilis. I have already stated that they are deported, 

 eventually by the blood current, into the connective tissue in the immediate 

 neighborhood of the photophore. After that, there are signs of their 

 transportation farther away, into the gills, the liver, &c. In the gills of 

 those individuals in which the photogenous cells have already disappeared 

 from a number of the photophores or are in an advanced stage of de- 

 generation, it is not at all uncommon to meet with granules which are of 



Fig. 2. 



Disintegration-products of 

 photogenous cells. 

 X76 5 - 



