506 ALIAS. [Vou. II. 
(Fig. 21, p/) forward and medianward from group 2 supra- 
temporal. The second or middle one (Fig. 21, #/) lies between 
the other two, and extends almost direct medianward from near 
the double group 17-17. The first line lies superficial to the 
parietal. It begins close to, or among, the pores of group 8 
supra-orbital, sometimes starting in or running across the edge 
of a pore so that one of its organs lies partly inside it. The 
second one lies superficial to the squamosal and parietal, just in 
front of the anterior edge of the extrascapula. It often ends 
close to the posterior end of the first line, the two almost meet- 
ing to form an angle. The third one lies superficial to the 
parietal and extrascapula, and usually extends much nearer 
the middle line of the head than the other two. In many speci- 
mens these six lines, three on each side, seem to radiate from a 
clear space directly on the crown of the head. This appearance 
is most marked in young specimens (Figs. 14, 15, and 16, Pl. 
XXXV.), in which the anterior line begins close to pore 8 supra- 
orbital, and 1s a direct continuation of the line of that canal. The 
first organ of the pit line often lies partly inside the tube of pore 8, 
and in one set of sections was entirely inside it, somewhat modified 
in shape and about midway between the next following pit organ 
and the regular terminal organ No. 7 of the canal. This organ 
No. 7 is inclosed in its canal much later than the other organs 
of the line, and is in specimens up to 45 millimetres in length 
much smaller, being still single while they are represented by 
groups of three or five. 
The horizontal line on the cheek (Fig. 22, 7) begins among 
the pores of groups 14 or 15 of the opercular line, and ends 
among those of group 12 infra-orbital. It lies partly superficial 
to the lower postorbital, somewhat behind the centre of the 
bone, and frequently runs directly into a pore of group 12, just 
as the anterior dorsal line does tnto the pores of group 8 supra- 
orbital. These two lines are the only ones tn which this occurs, the 
other lines beginning at some little distance from the pores of the 
groups near which they arise. The vertical line (Fig. 22, v/) 
begins behind or among the pores of group 12 infra-orbital, near 
the anterior end of the horizontal line, and, lying partly superfi- 
cial to the lower postorbital, runs downward toward the pores 
of group II operculo-mandibular, or a little behind them. The 
mandibular line (Fig. 22, md/) lies superficial to the angular, 
