INO. 3-.] LATERAL LINE OF AMIA. 507 
and runs, in the shape of a letter S, from the anterior part of 
group II toward group 9 operculo-mandibular. The gular line 
(Fig. 23, g7) runs transversely across the gular plate between 
groups 7 and 8 on either side. 
In the adult the bones immediately beneath these pit lines are 
slightly furrowed, and the lines are often broken. 
Body Lines. —In the adult there is, on nearly every scale of 
the first two-thirds of the lateral line, a line of pit organs run- 
ning across the scale immediately in front of the group of pores 
(Fig. 39, Pl. XX XIX., a//). In young specimens these lines are 
each represented by a single organ lying immediately above the 
corresponding organ of the lateral line. In the development of 
the pit line these single organs are apparently connected by a 
cord of cells, not only with each other, but also with the corre- 
sponding organs of the lateral line. The line grows backward in 
the same way that the main line does, and may be called the acces- 
sory lateral line, a name already used by Solger (No. 17, p. 380) 
and others. In the adult the first series of pit organs is found 
on the third, fourth, or fifth scale of the line; in one specimen 
which was examined for this purpose no organ could be found 
behind the forty-fifth scale, there being in all sixty-seven scales 
in the lateral line. Toward the head there are always more 
organs in each series or line, some of them having as many as 
eight. 
The first series of organs of the dorsal body line is usually 
found on the second row of scales, above and behind group 21 
infra-orbital (Figs. 15, 16, and 17). This row of scales is the 
second or third row of the body, counting backward along the 
middle line of the back, or the second row, counting along 
the lateral line. Considering the rows transverse to this, — 
that is, those that run upward and backward, — the dorsal body 
line begins on the sixth or seventh row of scales and on the 
second row in front of the first scale of the lateral line. Still 
considering these transverse rows, the second series of organs 
lies on the row following that on which the first series is found, 
and on the second scale dorsalward along that row. The third 
series lies on the next row, usually four scales dorsalward from 
the second series, and on the second scale from the middle line 
of the body. It lies in the same row as the first scale of the 
lateral line. From this point the pit line runs directly back- 
