No. 3.] FISUAL ‘GELES MIN@ BERT BE BTKALEES, 615 
at Schultze’s (’67, p. 218, Taf. 13) description of what he 
calls the “Kittsubstanz,” it is evident that he referred to the 
same object. The latter term has been since applied more 
generally to the substance between the plates of the outer 
segment. Herzog (:05) figures an intermediate plate in both 
individuals of the double cones in Rana, but I am not certain 
of its presence in the cones of Necturus. 
The ellipsoid or its homologue is found in most vertebrates. 
The name is hardly appropriate, for its usual form is not 
ellipsoidal; but such a term is better than ‘‘Aussenlinse,” 
which assumes that its function is dioptric. Schultze’s term, 
“outer lentiform body,” has nothing objectionable except per- 
haps its rather prohibitive length. In our present state of 
knowledge concerning the ellipsoid, its significance, I think, 
can only be surmised. I can hardly agree with Pes (:00) 
in his belief that it is a nucleus and that the visual cells 
extend as independent elements only to the membrana limitans 
externa. It is true that aside from what is usually taken to 
be the true nucleus, it 1s the distinctly chromophil portion of 
the element, and might have specialized nutritive functions, 
but I have not seen the slightest evidence that it ever exhibits 
karyokinesis. The visual cells, so far as I know, never divide 
normally in the adult animal, excepting possibly at the ora 
serrata. The highly refractive and clear appearance of the 
ellipsoid in the fresh condition, suggests a dioptric function, 
but again the frequent occurrence of globules within its 
substance is a fact not consistent with this view. That the 
globules are simply coagulation products is possible, yet they 
are perhaps too regular for that. In the cones of the gold- 
fish the spherules are separated by equal intervals and are 
very uniform in shape and size (see also Hesse, : 04, Taf. 25, 
Fig. 4,6; Chondrostoma, and First, : 04, Taf. 3, Fig. 27, trout). 
I have seen no connection between structures in the ellip- 
soid and the fibrils which pass over its surface. If, as has 
been supposed, the ellipsoid and paraboloid have each the 
function of a lens, we have here an interesting adaptation of 
