934 
SCANDINAVIAN FISHES. 
the postabdominal about 10 (11 — 9) %, of the length 
of the body. 
The whole body, forward to the interorbital space, 
is covered with extremely thin, transparent, rather 
large, and rounded scales, somewhat higher than long, 
and with scattered, concentric strife on the posterior 
part. There is no special lateral line, the scales of 
the median line being without pores. 
The luminous spots are distributed in the same 
manner as in Argyropelecus Olfersii, but more regu- 
larly. A comparison with Coccia ovata shows most 
clearly of all that they lie in three rows, though the 
middle row should probably be regarded as a ramifi- 
cation of the lowest, or vice versa. The uppermost 
row begins at the extreme front of the chin, and in 
Coccia runs back without a break along the branches 
of the lower jaw and on the branchiostegal membrane, 
one spot being situated between each pair of branchio- 
stegal rays, till the membrane coalesces behind with 
the interoperculum and suboperculum so completely 
that the luminous spots apparently lie on the inner 
surface of these bones. Above the row, on the inside 
of the lower preopercular angle, we find one spot, 
suggesting an upward ramification of this row. In the 
Pearl-side the row is interrupted along the branches 
of the lower jaw, only two spots, probably answering 
to the second pair in Coccia , appearing on the soft 
chin-space, and further back each of the branchiostegal 
membranes is furnished with 6 spots, which shine through 
the maxillaries and the horizontal (anterior) arm of the 
preoperculum. On the inner surface of the opercular 
apparatus the remaining spots are the same as in 
Coccia ". The lowest row of luminous spots starts from 
the anterior extremity of the isthmus, in Coccia quite 
at the mental angle, where the two lateral halves of 
the first mentioned row meet, and follows the ventral 
margin, in this genus without interruption, merely 
forming a curve at the beginning of the anal fin, back 
to the lower corner of the base of the caudal fin. But 
in front of the base of each pectoral fin and above this 
row, lies one spot, suggesting an upward ramification 
of the row, and on a level with the last-mentioned 
spot runs the upper ventral row, pair by pair with the 
spots of the lower row, and unbroken in Coccia to a 
line with the beginning of the anal fin. In the Pearl- 
side the lowest row begins similarly at the anterior 
extremity of the isthmus; but this extremity is situated 
further back, hardly in front of the perpendicular from 
the anterior margin of the eye, and the row runs on 
each side of the body, in an upward curve containing 
6 luminous spots, towards the base of the pectoral fin. 
At the ventral margin between the last pair of these 
spots, begins the true (lower) ventral row, which should 
thus be regarded here as a downward and backward 
ramification of the isthmian row, and runs on each 
side of the body to the lower corner of the base of 
the caudal fin. This row contains 43 spots, the pair 
at the base of each ventral fin (the 13th and 14th in 
the row) somewhat obliquely arranged, and the remain- 
ing 4 on the postabdominal region forming a slight 
upward curve. A slight break in the row occurs at 
the beginning of the anal firi (between the 18th and 
19th spots), and a similar break at the end of the same 
fin (between the 34th and 35th spots). The upper 
ventral row of luminous spots, which in the Pearl-side 
— to judge, at least, by its direction and the form of 
the spots — is a more immediate continuation of the 
isthmian row, begins in the upper part of the axilla, 
and runs, containing 9 spots, to a line with the base 
of the ventral fin, from which point it is interrupted 
throughout the postabdominal region, but re-appears 
in a single spot above the beginning of the anal fin. 
The spots in the upper ventral row, those between the 
branchiostegal rays, and most, if not all, of the pos- 
terior spots in the isthmian row, are obliquely cut and 
prolongated in a downward direction (see above, p. 
921, with note a). 
The coloration of the Pearl-side is almost the same 
as that of the smaller Herrings, a lustrous silvery white, 
but dark, shading into blue on a greenish ground, on 
the back and the top of the head. So long as the 
scales adhere, they give the sides of the body a tinge 
of yellow. The black rims of the luminous spots stand 
out sharply from the pale bluish (in spirit-preserved 
specimens yellowish) lustre of their interior; and where 
these rims touch, along the base of the anal fin and 
the inferior margin of the tail, there appears a coal- 
black band. The end of the tail itself is of the same 
colour as the back, and outside (behind) the tail a 
narrow, black band crosses the base of the caudal fin. 
“ The luminous spot which Moreau {Hist. Nat. Poiss. Fr ., tome 3, p. 511) observed in M aur aliens ameihystino-punctatus on each 
side of the snout, near the nostrils, we have not been able to detect in our preserved specimens of the Pearl-side; but it is distinctly shown 
in v. Wrights figure, small, but prolongated along the lower margin of the anterior part of the preorbital bone. 
