No. 3.] LATERAL LINE OF AMITA. 535 
the dorsal body line is also continuous with the cord of the 
lateral line; the cord of the supratemporal line, with organ 18; 
and the cords of the three dorsal pit lines and the lines on the 
cheek, with the canal organs, near which they arise. In slightly 
older specimens these connections disappear, and in still older 
ones even the cord connecting the organs of each line is traced 
with difficulty. In the 114-millimetre specimen there are, be- 
hind organ 18 infra-orbital, five faint transverse markings, as 
shown in Fig. 6. The first one marks the hind edge of the 
extrascapula, and the others the lines of intermuscular septa. 
Between the fourth and fifth lies the first regular organ of 
the lateral line. Between the others, organs I9, 20, and 21 
will doubtless appear; but this could not be established, for 
when these organs are first seen, the intersegmental markings 
have disappeared. 
General Summary. 
The sense-organs of the lateral system in Amia are separated 
by their position and by their innervation into distinct groups. 
Each group develops from a special cord of cells lying in the 
deeper layers of the epidermis, and each cord from a special 
sensory thickening, which when first seen from the surface in 
specimens hardened in chromic or picro-sulphuric acid, appears 
as a large, whitish, and slightly raised spot. These spots are the 
rudiments, not only of the different groups of organs, but also, 
according to the theory of Beard and others, of the nerves 
supplying them. They are all distinctly recognizable before the 
close of the first day after hatching. From them are developed 
the following groups of organs :— 
1. The first sixteen organs of the infra-orbital canal, and 
the one organ of the spiracular canal, all innervated by the RX. 
buccalis facialis, and its posterior division, the R. ofzcus. 
2. The seven organs of the supra-orbital canal and those of 
the anterior dorsal pit line, all innervated by the R. ophthal- 
micus factalis. 
3.. The sixteen organs of the operculo-mandibular line and 
those of the two pit lines on the cheek and the one on the 
mandible, all innervated by the R. mandtbularis externus. 
4. Organ 17 infra-orbital and those of the middle dorsal pit line, 
all innervated by the dorsal branch of the WV. glossopharyngeus. 
