1026 
SCANDINAVIAN FISHES. 
long the corresponding percentages were respectively 
4'3 and 10. In the males the former percentage varied 
between 3'0 and 3*7, in the females between 3'8 and 
4‘5. The latter percentage varied in the males between 
7'5 and 8*6, in the females between 9 and 10‘9. That 
this sexual difference — as it appears in the above 
measurements — is fully constant, enabling us in every 
instance to distinguish between males and females, is 
hardly probable, for it coincides with a marked altera- 
tion of growth; but it would seem at least to show 
that the males retain the characters of youth longer 
than the females®. 
The thick and tough skin completely envelops even 
the tins, but owing to the underlayer of lax connective 
Fig. 276. Scale of Anguilla vulgaris. About 23 times the natural size. 
tissue and fat is so loosely attached — as every kit- 
chenmaid should know — that it can easily be stripped 
off entire. The copious slime that covers it has ren- 
dered the Eel’s slipperiness proverbial; and the system 
of the lateral line is well developed. The lateral line 
itself, which is straight, lying about half-way up the 
sides, in front somewhat higher, so as to meet the 
temples, is made up of comparatively scattered pores, 
on the tail often indistinct, and not supported by spe- 
cial scales, but usually marked off by their light hue 
from the ground-coloration. The cephalic system of 
the lateral line shows a transverse roAv of pores across 
the top of the head behind the eyes, from which they 
are separated by a distance about equal to the length 
of the snout; and on each side runs a i*oav, usually 
containing three distinct pores, straight fonvard from 
the transverse toav, toAvards the superior margin of the 
eyes, but not extending half-Avay thither. More distinct 
are the pores on the snout, one roAv on the turbinal 
bones and the suborbital ring, another on each half 
of the mandible. The scales, which are entirely im- 
mersed in the skin, are thin, flexible, and of a pro- 
longated elliptical shape, someAvhat constricted at the 
middle of their length, Avhich is about half the dia- 
meter of the eyes. On the sides of the body their 
arrangement is such that a certain number, usually 
3—5, lie beside and contiguous to each other, obliquely 
across the longitudinal direction of the body, and on 
each side of this group lie others, the scales of Avhich 
are set at about right angles to the former. Or each 
group may be longer, containing up to a score of 
scales, and forming a straight or curved row. Or the 
scales may be juxtaposited one by one, in the said 
zigzag arrangement. On the belly the scales are more 
scattered, and more nearly approach to the longitudinal 
direction of the body. The texture of the scales is 
highly characteristic. When slightly magnified, the 
entire surface seems to be composed of dense strings 
of lustrous beads, all parallel to the margin. When 
the scale is more powerfully magnified (fig. 276), this 
conformation dissolves into a honeycombed network, 
due to the union of the concentric striae (ridges) round 
the elongated, central nucleus by radiating ridges of 
equal elevation. 
The coloration of the Eel varies Avith age, the 
season of the year, the haunt of the fish, and partly 
too Avith its sex. The dorsal side is of a lighter or 
darker, greenish or grayish colour, the ventral yelloAv 
or Avhite; the middle of the sides has a bronze lustre 
of varying intensity. The colour of the fins usual ly 
resembles that of the back, except in the case of the 
a How futile it is to rely on the external sexual characters hitherto assigned in literature to the Eel, is most clearly shown by the 
conflicting results at which different writers have arrived. According to Jacoby ( Fischf . Comacchio, Berlin 1880, p. 40) the males have 
pointed snouts. From his measurements (p. 41) it appears that the breadth of the snout at the nasal ducts — (I assume that “Breite der 
Schnauzenspitse zwischen den Nasaltuben” must be taken in this sense, for “between” the nasal tubes I have never found the distance so 
great) — measured in 8 males (319 — 480 mm. long) less, in 8 females (313 — 480 mm. long) more, than 12 % of the length of the head. 
According to Lilljebobg (Sv., Norg. Fisk., vol. Ill, p. 382) the males most commonly have blunt, “sometimes pointed” snouts. 
