582 HOWARD. [ Vou. XIX. 
scarcely be distinguished distally between it and the intermedi- 
ate plate and proximally between it and the paraboloid (PI. 1, 
Pic. 1; Pl. 2, Figs. 7,78). lprseems ‘probable, owever,.wemdr 
there is in all cases a separation and that the ellipsoid is a dis- 
tinct body entirely enclosed. 
The paraboloid in this material often has an ellipsoidal form 
(normal), but is almost as frequently flattened by pressure. 
This seems to be due to a forcible contraction in fixation, of 
the “rod myoid,” a name given by Greef (:00) to the con- 
tractile part of the inner segments of the rods and cones. 
In Necturus this myoid ts often little more than a sheath to the 
paraboloid. As the ellipsoid and nucleus are hardened more 
quickly than the paraboloid, the latter is moulded to them. 
The substance of the paraboloid is chemically unlike that 
of the ellipsoid, since most stains affect it but little. A close 
study of material stained in hematoxylin reveals a very close 
reticulume (Ply 1, Pigs. 1, 4, 7a10:0Ge. Fl oiic. 20) omtaae 
same material stained with Mallory’s (:00) triple stain gives 
a coarser meshwork of a blue staining substance having nodal 
dots (Pl 2 hic 8) pa bebac.): 
In the periphery fibers are demonstrable in both lateral and 
sectional views, as in the parts of the rod previously described. 
Here, however, a clearly defined sheath of considerable thick- 
ness is present (the myoid described above), and in this the 
fibrils are deeply imbedded. Lying close to the paraboloid 
the fibrils (Pl. 1, Fig. 4, B. fbrl.) pass over the surface of the 
nucleus, as can be seen by cross sections of the latter at the 
distal end (Pl. 1, Fig. 5, B., fbri.) or in lateral view of the 
nuclei in radial sections of the retina (Pl. 2, Figs. 7, 8, fbrl.). 
I have not succeeded in demonstrating with certainty fibrils 
in cross sections of nuclei, where the latter are closely packed. 
Proximal to the nucleus the fibrils are sometimes convergent 
to the foot process and then divergent (Pl. 2, Fig. 8) ; in other 
cases there is no convergence (Pl. 2, Fig. 7, fbrl.), but the 
fibrils spread from the end of the nucleus directly out into 
the reticular layer. 
