THE RADIATING ORGANS OF THE DEFP SEA FISHES. 185 
edrical cells in the centre, and cylindrical elements on the surface. The 
latter (Plate 9, Figs. 43, 44 pe) resemble a cylinder epithelium clothing the 
pigment sheath and distal connective-tissue membrane internally. They 
are not vertical to this surface however, but so arranged as to converge 
to a point within the organ very near its proximal apex. In the distal 
part of the organ these cells are short, hardly longer than broad. Inwardly 
they increase very rapidly in length and those situated at the sides are 
nearly half as long as the organ itself. The nucleus is conspicuous, spheri- 
cal, or radially extended, oval, and always situated at the distal end of the 
cell. The protoplasm is granular, The limits between these cells are 
distinct enough distally, but become very indistinct centrally and finally 
vanish altogether; in the proximal part of the organ to which these cells 
converge, no trace of cellular division is discernible. ‘This part of the organ 
is occupied by a granular protoplasmatic mass (Plate 9, Figs. 43, 44 m) 
in which neither cell walls nor nuclei are met with. The proximal apex 
itself is in the regular oval organs free from these cells, or cells of any kind, 
the granular mass (m) extending here right up to the pigment sheath 
(Plate 9, Fig. 43). In the axial sections of irregular organs, however, a net- 
work of cell limits with nuclei in the meshes is usually observed in the part 
appearing as the proximal apex (Plate 9, Fig. 44). It seems to me, however, 
that this point does not exactly correspond to the proximal apex of the 
regular organs and that the “cells” seen there are transverse sections of 
the same kind of superficial cylinder cells as appear cut longitudinally else- 
where. These organs being so very irregular in shape, an irregularity in 
the arrangement of the superficial cylinder cells, giving rise to such an 
appearance of axial sections, would be not at all surprising. 
The inner mass of polyedrical cells (Plate 9, Figs. 43, 441) has the shape 
of a bee-hive or truncate cone resting with its broad base on the distal 
cylinder cells and extending inward a good way beyond the centre of the 
organ. The distal cells of this mass are smaller and arranged irregularly, 
the proximal ones larger and situated in more or less clearly pronounced 
In their appearance these cells differ essentially from 
longitudinal rows. 
the cylindrical elements surrounding them. ‘Their nuclei are pretty large, 
spherical, or flattened radially, and their protoplasm is transparent and free 
from granules. Picric acid stains them a bright yellow. The superficial 
cylindrical cells are comparable to the cells forming the inner region of 
such radiating organs as those described above of Argyropelecus and Ster- 
