1160 
SCANDINAVIAN FISHES. 
The two dorsal tins in their relative position to 
each other resemble those of the Tope; but their form 
approaches more nearly to the square, and each of 
them is furnished at the anterior margin with a fairly 
stout and strong spine. As a rule the second dorsal 
tin is perceptibly smaller than the first, about 3 / i as 
large; but its spine is the larger, being even higher 
than the fin itself, whereas the spine of the first dorsal 
extends only about half-way up the anterior margin 
thereof. The spines are pointed, somewhat curved, and 
triangular in section, with the whole posterior surface 
concave, but with rather convex side-margins. The 
first dorsal fin commences at about the end of the first 
third of the length of the body, the second dorsal at 
the termination of the second third thereof, somewhat 
further forward in the adult males than in the females, 
and further back in the young of both sexes than in 
the old. The length of the base of the first dorsal is 
about equal to the interorbital width. The base of the 
second dorsal measures about 4 / 5 — ®/ 4 of that of the 
first. The caudal fin is distinguished partly by the 
a b 
Fig. 339. A scale of the Picked Dog-fisli ( Squahis acantluas), seen 
from above (from without, a, with the retral tip directed upwards in 
the figure) and from the side ( b , with the retral tip turned to the 
right of the figure). About 37 times the natural size. 
slight upward curvature of the tip of the tail within 
the fin, partly by the greater relative breadth of the 
upper lobe than in the preceding Sharks and the ab- 
sence of incision in the hind part of the inferior mar- 
gin of the fin. The length of the upper anterior mar- 
gin of the fin is in the males somewhat more, in the 
females somewhat less, than x / 5 of the length of the 
body. The lower anterior margin is about half as long 
as the upper or a little longer. 
The pectoral fins indeed approach to the more 
spatulate form they exhibit in the following Sharks, 
but they remind us of the preceding species in the 
marked prolongation of the posterior inner corner, the 
hind margin being thus rendered concave. The distance 
between them and the tip of the snout is about x / 5 of 
the length of the body, and in the males about 2 / 3 , in 
the females about 4 / 5 , of that between the first dorsal 
fin and the same point. The length of their anterior 
margin measures about 80 — 95 % of that of the head 
— relatively less in the young — - and the breadth of 
their base about 34 — 40 % of their length. The ven- 
tral fins are obliquely lozenge-shaped, or resemble an 
obtuse-angled triangle, when the fins are laid back, in 
which case the base is continued, without a break, by 
the inner posterior margin. The distance between them 
and the tip of the snout in the males is about 50 — 
52 % , in the females about 53 — 54 %, of the length of 
the body. Their base together with their inner pos- 
terior margin measures about 9 or 10 %, their anterior 
margin about 5 or 6 %, of the length of the body. In 
adult males the distally flattened pterygopodia project 
far beyond the ventral fins, and are furnished on the 
upper surface with a broad dermal groove, in which 
tAvo spines are concealed, the one long and hamatelv 
curved at the tip, the other, which is visible in our 
figure (PI. LII, fig. 1), pointed, grooved, and serrated. 
The skin is uniformly shagreened with scales of a 
singular form (fig. 339), elevated on a terete shaft, at 
the top of which they are rectangularly bent and ex- 
panded behind in a three-pointed foliate form, with the 
middle point longest and most powerfully strengthened 
by a median ridge, passing into the anterior margin 
of the shaft, on Avhose sides the lateral ridges are also 
continued. 
The coloration is above grayish broAvn, more or 
less dark, shading doAvn the sides into violet, with a 
feAv small, roundish, Avhitish spots set in a roAv along 
the anterior half of the lateral line and in another row 
along the back, Avhich latter series is much sparser, but 
is continued in very young specimens back to the tail. 
The belly is pale and whitish, but finely punctated with 
dark dots. After death the colour of the back soon 
fades and becomes more grayish, but it may be better 
preserved by depositing the specimen at once in strong 
spirit. 
The external difference of sex may be traced in 
unborn foetuses 1 8 cm. long. The males among these 
have fairly distinct pterygopodia, Avhich are, hoAvever, 
only half as long as the inner margins of the ventral 
fins. These young specimens are almost similar in form 
and coloration to the adult individuals, only that the 
tip of the snout is someAvhat shorter, the distance be- 
tween the nostrils .and the extreme tip of the snout 
being only about 2 / 3 of that between them and the 
mouth, and that the dorsal fin-spines are short. The 
posterior of these spines measures only 2 / 3 of the height 
