Bains 
THE RADIATING ORGANS OF THE DEEP SEA FISHES. 201 
walls similar to those observed by Leydig and others in certain cells of the 
ocellar radiating organs described above. If on the other hand intercellular 
spaces are really present — and the appearance is in favor of this assumption 
— the question arises whether they are present in these cell plates in life or 
merely artifacts produced post mortem by transverse cell shrinkage. In the 
lower end of each of these cells a large oval granular nucleus is observed. 
These nuclei form a single layer in the basal part of the plate. In the 
marginal zone nuclei are also observed higher up, and the same is the case 
in the central groove, where a few nuclei are likewise seen at a higher level. 
It is doubtful, however, whether these latter belong to the cylinder cells. It 
seems rather that they are the nuclei of slender spindle cells here interposed 
between the cylinder cells. The protoplasm of the cylinder cells is pretty 
granular and stainable with acid-fuchsin and haematoxylin. These stains 
are taken up more by the terminal than by the central parts of the cells. 
The cells of the central groove show a marked affinity for picric acid; other 
stains are hardly at all absorbed by them. 
Transverse sections (Plate 11, Figs. 56, 57) show that the intercellular 
spaces between the cylinder cells above mentioned do not extend quite to 
ends of the cells, in 
the upper surface of the cell plate. Here the upper 
with each other and 
most cases considerably curved, are in direct contact 
form a superficial pellicle apparently quite continuous and in sections some- 
what resembling a cuticle. 
[ have previously described (’87, pp. 809-313, Plate 73, Figs. 45-48, 54-64) 
the structure of the radiating discs in another species of Halosaurus, H. 
macrochir, In this species a pair of large glandular radiating organs also 
have a different structure. The 
c 
occurs under the gill covers. These 
smaller spindle-shaped discs on the sides of the body, however, resemble the 
radiating discs on the head of /7. radiatus pretty closely. These are in H, 
macrochir attached to the outer side of the scales over the great lateral slime 
canal. Below the centre of each digse the scale is perforated by an oblique 
tube through which a nerve and blood vessels ascend to the base of the disc. 
In the disc itself a lower layer, chiefly occupied by an exceedingly close 
reticulation of capillary blood vessels, and an upper composed of slender 
cells arising vertically, standing side by side, and forming a high epithelium 
The individual elements of the latter are spindle- 
can be distinguished. 
In transverse sections through the disc 
shaped or irregularly cylindrical. 
these cells appear separated by clear intervals wider than in the cylinder 
