iir.o 



SCANDINAVIAN FISHES. 



Tlie two dorsal tins in their relative position to 

 each other resemble tiiose of the Tope; ])ut their form 

 approaches more nearlj' 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 

 fin is ])erceptibly smaller than the first, about '/^ as 

 large; but its spine is the larger, being even higher 

 than the fin itself, whereas the spine of the first dorsal 

 extends ordy about half-way up the anterior margin 

 thereof. The spines are pointed, somewiiat curved, and 

 triangular in section, with the whole posterior surface 

 concave, but with rather convex side-margins. The 

 first dorsal fin commences at al)out 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 doi'sal is 

 about equal to the interorbital width. The base of the 

 second dorsal measures about ''/j- — ^/^ of that of tiie 

 first. The caudal fin is distinguisiied partly by the 



a h 



Fig. 3.^9. .\ scale of the Picked Dog-i3sli {i^ipiahis acant/iias), seen 



from nbove (from willioiit, a, with the retral tip directed upwards in 



the figure) and from tlie side (4, witli tlie retral tip turned to the 



riglit of the figure). About 37 times the natural size. 



sliglit ujjward curvature of tlie tij) of the tail witliin 

 tile fin, partly by the greater relative breadth of tlie 

 upper lobe than in the preceding Sharks and the ali- 

 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 somewdiat more, in the 

 females somewhat less, than '/j 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 

 S[)atulate form they exhiliit 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 ^j of 

 the length oi the body, and in the males a,bout '/^, in 

 the females about "5, of that between the fii'st dorsal 

 fin and the same point. The length of their anterior 



margin measures about 80 — 9.5 96 of tiiat 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 l)aek, in 

 ■which case the base is continued, without a break, by 

 tlie 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. TJieir 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 

 two spines are concealed, the one long and hamately 

 curved at the tip, the other, which is visible in our 

 figure (PI. LIl, fig. 1), pointed, grooved, and serrated. 



Tiio 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 po-\verfidly strengthened 

 by a median ridge, passing into the anterior margin 

 of the shaft, on whose sides the lateral ridges are also 

 continued. 



The coloration is above grayisii lirown, more or 

 less dark, shading dow^i the sides into violet, ^^•ith a 

 few small, roundish, whitish spots set in a row along 

 the anterior half of the lateral line and in another row 

 along the back, which latter series is umcli sparser, but 

 is rontimied in very young specimens back to the tail. 

 Tlie lielly 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 firtuses 18 cm. long. The males among these 

 have fairly distinct pterygopodia, which are, how'ever, 

 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 tiie snout is somewhat shorter, the distance be- 

 tween the nostrils and the extreme tip of the snout 

 being only about "3 of that between them and the 

 mouth, and that the dorsal fin-spines are short. The 

 posterior of these spines measures only V3 of tl^^ height 



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