190 THE RADIATING ORGANS OF THE DEEP SEA FISHES. 



The proximal cone described by Leuckart is part of this latter. In the distal 

 cap club-shaped cells are met with, the distal end of which is the thicker 

 one. It is laterally enclosed by stout cell walls, but destitute of a terminal 

 membrane. The thin proximal end passes into a fine thread of considerable 

 length. The nucleus is situated in the lower end of the thick part of the 

 cell. The cells of the lower mass of the distal portion are of greater size, 

 more finely granular, and have a larger nucleus. The proximal cone 

 appears to be composed of processes of these cells which converge towards 

 its apex. This cell mass is traversed by fibrous strands, extending inward 

 from the surface and forming a kind of scaffolding which has the shape of a 

 honey comb. The cells of this honey comb evidently correspond to the 

 connective- tissue facets described above of C. harhatns. The cones occupy- 

 ing the proximal part (inner region) of the organ are cells. Leydig found a 

 nucleus in their granular outer end. The centre to which these conic cells 

 converge is occupied by a finely granular substance (" Punktsubstanz ")• 

 Leydig thinks that the nerve leading to the organ terminates in this " Punkt- 

 substanz " and that the cells both above (cone of the middle region) and 

 below (inner region) are connected with it. A portion of the reflector form- 

 ing half a ring outside the stricture has a distinctly golden lustre. Leydig 

 calls these organs accessory eyes, but uses this term (" Nebenaugen") with 

 a certain amount of mistrust. From this and from a quotation of Willemoes- 

 Sulim, which he publishes, one can conclude that he was already at that 

 time, although calling these organs eyes, quite open to the view that they 

 had in fact a radiating function. 



Tlie descriptions given by these authors are based on material insuffi- 

 ciently preserved and studied without the application of modern methods. 

 They can therefore claim hardly more than an historical interest. Now, 

 however, we have to review the papers by Brandt (1899) and Chiarini (1900) 

 in which the compound radiating organs of Chaidiodus sloani are described in 

 a far more exact manner. , 



According to Brandt's description ('99, pp. 447-450) these organs of 

 C. sloani seem to be identical in structure with those of C. harhatus. He 

 considers the cells of the inner region as gland cells in which a secretion 

 is formed and then oxidized whereby light is produced, whilst the middle 

 and outer region have no otlier function than that of conveying the ra- 

 diation produced to the outer world. 



Chiarini ('00, pp. 14-17, Figs. 6-7) also describes the radiating organs of 



