447 
The tenth sensory patch lay on a scale of the same row as the 
ninth patch, lying on the first scale ventro-posterior to the one on 
which that patch was found. It thus lay on the ninth scale of the 
eighth row posterior to the posttemporal bone. From here the lateral 
line ran directly backward, always on the same level, to the base of 
the tail fin, a sensory patch being found on each and every scale of 
the line. There were, in the 44-cm specimen, 55 scales in this part 
of the line. 
No sensory patches or sense organs could be traced on the tail 
fin itself. 
On the right side of the body of this same specimen the arrange- 
ment of the lateral scales was slightly different, and it apparently 
varies somewhat, in every specimen. The first three lateral scales on 
this side of the 44-cm specimen, for example, were the sixth scales of 
their respective rows, and lay one directly posterior to the other. The 
line then dropped one scale ventrally, the first scale of this second level 
lying in the same row of scales as the third scale of the first level. 
In the second level there were four scales, each scale being the seventh 
scale of its respective row. ‘The line then skipped one row of scales, 
at the same time dropping ventrally to a third level. The eighth sen- 
sory patch of the line thus lay on the eighth scale of the eighth row 
of scales posterior to the posttemporal bone. The next scale of the 
line lay on the same row of scales as the eighth one, but one scale 
ventral to it. From here the line continued backward, at the same 
level, to the tail. The first scale of the main level of the lateral line 
thus lay, on each side of the head, on the eighth row posterior to the 
posttemporal bone, and on the ninth scale of that row. 
In addition to the sensory patches of the main lateral line there 
is, in Polypterus, a dorsal body line of sensory patches, and another, 
somewhat irregular, line lying midway between the lateral line and the 
dorsal body one. Both of these lines are shown in Acassız’s (No. 1) 
figure of the fish. 
The dorsal body line, in the 44-cm specimen, began, on both sides 
of the body, on the second scale of the sixth row of scales posterior 
to the posttemporal bone. From there it ran backward, in a fairly 
regular line, to the hind end of the body, lying always one or two 
scales removed from the mid-dorsal line until it had passed the last 
dorsal finlet, of which there were sixteen in this specimen, and had 
reached the level of what may be considered as the beginning of the 
tail fin. There it dropped one scale ventrally, and then continued 
backward to the root of the tail fin. In this part of its course it lay 
