468 LANDACRE AND McLELLAN 
length dorso-ventrally, but the jugular extends farthest forward 
and the dorsal lateralis farthest posteriorly. 
The second group (figs. 1 and 2) consists of two ganglia, the 
ventral lateralis (V.L.X.) and the second division of visceral X 
(G.V.X?). This second group les directly ventral to the first 
group. In this second group the ventral lateralis is lateral and 
the visceral ganglion is mesial. These two ganglia are approxi- 
mately equal in their dorso-ventral length but antero-posteriorly 
the visceral is broader. 
The third group (figs. 1 and 2,G.V.X") consists apparently of 
two branchial ganglia fused, since two branchial nerves arise 
from it, but is treated here as one ganglion. It occupies the same 
level dorso-ventrally as the second group, but in general shape is 
much like the [X ganglion. Its long axis, unlike the two preceding 
groups, is in the anterior posterior plane and at its posterior end 
it is fused with the second division of visceral X. 
THE DORSAL LATERALIS X 
This ganglion (figs. 1, 2, 6, 10 and 11), as mentioned above, 
occupies the lateral portion of the proximal division of X. It is 
also the most dorsal portion of the ganglionic complex. It is 
somewhat elongated dorso-ventrally, not reaching so far forward 
as the jugular, but extending considerably posterior to any other 
portion of the X. It begins abruptly in a rounded anterior end 
and diminishes in size as one reads posteriorly, where the most 
dorsal of the rami laterales take their origin at the extreme pos- 
terior end of the ganglion. The ventral border of this ganglion 
is in contact in the later stages, but not in the earlier stages, with 
the dorsal portion of the ventral lateralis X. The resemblance 
of this ganglion to the lateralis X ganglion in Ameiurus and Lepi- 
dosteus (Landacre ’10 and 712) at similar stages of growth is 
striking. The large size of its cells, its position, its clean-cut 
boundaries and the extension of its posterior border beyond the 
posterior limits of the remaining ganglia mark it at once as the 
same ganglion. Its position with reference to the jugular and 
visceral X is the same in all three embryos. 
