148 ROY L. MOODIE 
possible, to correlate correctly all parts of this fossil brain with 
the parts of the brain of modern fishes. We may be certain of 
the optic lobes, however, and some other features, such as the 
olfactory lobes and tracts; but other structures are not so readily 
determined and the interpretations placed on them are tentative. 
It is not possible to identify them with certainty. The form of 
the brains of fishes vary to suit the adaptation of the animals 
to their environment and, since we do not know the environment 
of this Coal Measures fish and since internal structure is impos- 
sible of determination, we must do what we can by tentative 
determination. 
The spinal cord is se partially represented, if at all, by a 
short portion on the very margin of the nodule. The vagal lobe, 
which is single and median, projects backward over the fourth 
ventricle. In the specimen shown in figures 15 and 16 the top 
of the vagal lobe has been destroyed, but other specimens in- 
which it is preserved as a mold show it as median and unpaired. 
In the generalized types of recent fishes the vagal lobes are de- 
veloped as paired eminences in the lateral walls of the fourth 
ventricle, and this is the condition in all known forms of cyclo- 
stomes, elasmobranchs and ganoids. These vagal lobes, or vis- 
ceral lobes, unite across the mid-plane dorsally above the ventricle 
immediately below the calamus scriptorius in the commissural 
nucleus of Cajal. This is the usual condition in teleosts also, 
though here the vagal lobes are usually larger and more com- 
pact. In some teleosts (e.g., the catfish and other siluroids) 
there are two pair of these visceral lobes in front of the com- 
missural nucleus, related respectively with the visceral sensory 
roots of the IX + X and VII cranial nerves. These are the 
vagal and facial lobes. In the carp and other cyprinoid fishes 
these lobes are greatly enlarged and there are three separate 
visceral lobes in front of the commissural nucleus—a pair of 
very large vagal lobes, a pair of much smaller glossopharyngeal 
14 Herrick, C. Judson. 1908. On the commissura infima and its nuclei in the 
brains of fishes. Jour. Comp. Neur., vol. 18, pp. 409-431. 
1° For an illustration of this relation see, Herrick, C. Judson. The central 
gustatory paths in the brains of bony fishes. Jour. Comp. Neur., vol. 15, 1905, 
p. 382, fig. 4. 
