196 THE KADIATING ORGANS OF THE DEEP SEA FISHES. 



minal f.ace of the cylinder is rounded off, simple, convex ; the inner, proxi- 

 mal face is drawn out to form a regular cone about as high as broad, which 

 penetrates the mass of radial conic cells occupying the proximal spherical 

 part of the organ. The apex of this cone lies a little way above the centre 

 of this sphere. The whole appears as a cylindroconic plug (Plate 10, Fig. 

 51). From that part of the connective-tissue capsule of the organ which 

 covers the terminal face of this plug, diverticula extend inwards parallel to 

 the axis. These form parallel facets. The central (axial) facet (cc) is the 

 longest ; it extends to the apex of the cone, whilst towards the sides of the 

 cylinder the facets become shorter. Transverse (Plate 10, Fig. 49) and 

 longitudinal axial (Plate 10, Fig. 51) sections of the plug-shaped outer part 

 of the organ show that the contents of the central facet (Plate 10, Figs. 49, 

 51 cc) are different from those of the other facets (pc). In staining with 

 Van Gieson's haematoxylin-picric acid-fuchsin one finds that the latter take 

 up ha.ematoxylin and acid-fuchsin very readily, whilst the substance in the 

 central facet absorbs only the picric acid. It also stains with eosin. In the 

 distal parts of the outer facets nuclei and cell limits can be distinctly seen ; 

 here pretty large elongate cells are situated. In transverse sections of the 

 distal part of the plug one sees two or three cell sections lying side by side 

 in each facet (Plate 10, Fig. 49). In the proximal parts of the outer facets 

 and throug-hout the whole lengi-th of the central flicet cell limits cannot be 

 made out and nuclei are hardly to be seen. 



Ussow ('79, p. 91) has described these organs in Stomias harhatus. He 

 says that they are similar to those of Chauliodus, but that the middle region, 

 which he represents as a mushroom-shaped body (see above) in Chauliodus 

 sloani, is absent in Stomias harhatus. 



Organs similar to these have been described by Chiarini ('00, p. 12, Fig. 3) 

 from MauroUcus poweriae. He says that each of the cells of the inner spheri- 

 cal part and also of the cylindroconic plug, that is, the " neck " of the organ, 

 often contain t/ro nuclei. These cells are always mononuclear in Stomias 

 hexarjonatus. In longitudinal sections the limits between the cells are often 

 so indistinct that one can indeed be easily misled on this point and imagine 

 that the two or three nuclei seen imbedded in an apparently continous pro- 

 toplasmatic mass belong to one and the same cell. Transverse sections, how- 

 ever, show, at least in the distal part, the cell limits well enough and make it 

 clear that here each nucleus belongs to a separate cell. 



Tlie compound radiating organs of the second kind which are met with 



