302 J. B. Johnston 
Explanation of the Figures. 
Text figures. 
Figures 1—15 are made with the ABBE camera lucida and ZEISS apochro- 
matie Oc. No. 4, Obj. 8 mm. They are drawn from the series of sections used 
for reconstruction in Plate V,. and the number of the section drawn is placed 
in the lower part of each figure. In all of the figures cartilage is shaded by 
oblique lines, and dense fibrous tissue such as the membraneous eranium is 
shaded by very light wavy lines. T'he loose connective tissue found between 
the eranium and muscles and surrounding the ganglia is indicated by heavy 
lines. Blood vessels are outlined but not lettered. 
Fig. 16 is drawn with the camera under Obj. 2 mm, Oc. No. 8. It shows 
the appearance and relative size of the lateral line nerve in (550) an inter- 
segmental space near a dorsal spinal nerve, and (509) opposite a myotome near 
a ventral spinal nerve. 
Fig. 17 is a reconstruction of the branchial nerves, VII, IX and X,, upon 
a horizontal section through the gill openings. Only the left side is shown. 
The relative position of the gill openings and of the taste buds is indicated 
by arabie numerals showing the sections of the transverse series in which 
these structures fall. 
Fig. 18 is a diagrammatie transverse section through the first gill opening 
and the set of taste buds opposite to it; in which is sketched the course of 
the glossopharyngeus nerve. 'T'he numerals refer to sections in the series used 
for the description. 
Plate V. 
This is a graphie reconstruction on the median sagittal plane intended 
to show the course of the nerve components as described in the text. All 
those fibers wliich have similar peripheral distribution and similar central con- 
nections, and hence similar functions, are treated as belonging to one 
system. Any given nerve trunk or ramus may be made up of components 
belonging to two or more distinet systems. Each nerve has been analyzed 
into its components and all the fibers belonging to a given system have been 
represented by the same color, in whatever nerves they occur. Thus the ge- 
neral cutaneous components, which are present in all the dorsal nerves, are 
shown in light blue. The colors used for the several components are indicated 
in the lower left-hand corner of the plate. 
