llKi 



SCANDINAVIAN FISHES. 



The snout is pniloiigated in a sccuriforin shape. The 

 ]josterior side-margins of the disk are ai'cuate, with 

 a slight inward curve near the tip of eacli pectoral fin. 

 The ventral fins are conically pointed and rounded, 

 rather long, their length, measured fi-om the sacral 

 prominence, Ijeing not natch less than ' ,, of the entire 

 length of the tail, measured from the same ijoint. Tlie 

 body as a whole is fiat and not fleshy, its depth at 

 the shoulder-girdle being only about 9 ® of the greatest 

 breadth of the disk. The tail is furnished, as in the ])re- 

 ceding Rays except the Thornback, with two juxtaposited 

 dorsal fins, often united at the base. The hind margin of 

 the posterior lies half a fin-length from the tip of the tail, 

 which bears above a low and almost seraicircida.r caudal fin. 

 The length of the head to the occiput measures in 

 specimens 1 m. long about 18 % of the length of the body 

 or 30 % of the breadth of the disk. The length of the 

 snout as stated above distinguishes the Shagreen Skate, 

 as well as the following species, from the preceding 

 forms of the genus, but the distinction is least marked 

 in the Shagreen Skate, as appears from the relation 

 between this length and the least interorbital width of 

 the forehead. The latter is at least aliout 3U — 3o % 

 of the length of the snout from the anterior margin 

 of the eyes. The longitudinal diameter of the eyes is 

 about half the interorbital width. The spiracles, which 

 are almost transversely set, are of about the same size 

 as the eyes. The mouth is liroad and curved, power- 

 fully armed with teeth. The form of the teeth is also 

 highly characteristic, and among the other Scandinavian 

 Raj^s there is none with whose dentition it can be con- 

 fused. Each tooth (fig. 320, a) has a fairly long, un- 

 guiform crown, subulate at the tip, with some\vhat 

 compressed sides and without other indication of the 

 ordinarj' basal rim than a very small intumescence on 

 each side. The largest teeth are set in the middle of 

 the jaws, and their size decreases towards the corners 

 of tlie mouth. All these teeth are arranged in about 

 60 regular, longitudinal rows, which, in consequence 

 of the length of the pointed crowns, the superimposed 

 (imbricated) position thereof, and the fixed intervals 

 between the I'ows, have a resemblance to thin ridges, 

 fitting in between each other when the jaws are closed. 

 The internasal width is about Vs' — V3 greater than the 

 least interorbital width (120 — 133 ?o), somewhat more 

 than half (55 — 60 "/o) of the distance between each 

 nostril and the tip of the snout, and about 1 2 % of that 

 between the tip of the snout and the anus. 



Among all the Scandinavian Ravs the present spe- 

 cies has the most shagreened skin. The whole up])er 

 surface of the body is covered everywhei'e \vith dense, 

 but \crv short spinuke, ])artly pointed with stellate 

 base, partly granular and hardly distinguishable to the 

 naked eye. On th(! snout, both above and below, 

 throughout the anterioi' side-margins of the disk, 

 and throughout the ui)per and under surfaces of the 

 tail, these spinuhp show a somewhat greater develo])- 

 ment, and with their pungent tip, recur\'ed in a hamate 

 form, they greatly resemble, on a small scale, the aculei 

 proper. The ventral side too is strewn with spiiuila-, 

 but more sparsely, large patches of smooth and naked 

 skin being left on the pectoral and ventral fins, in the 

 anal region, and at other points. The ordinarv aculei 

 have an expanded, stellate or grooved, laterallv com- 

 pressed, and flat base and a haraately recurxed tip. 

 Two short rows of small aculei, vai'ving in numlier 

 and size, are set on the rostral cartilage. In a semi- 

 circle around the inner margin of each orbit runs a 

 row of larger, but unecjual aculei, the middle ones, 

 however, often absent or lost. The spinal column be- 

 tween the head and the scapular cartilage is followed bv 

 a series of aculei. 8 — 10 in ninnber and not very large, 

 and sometimes a row of still smaller ones skirts this 

 series on each side; but often only vestiges of these last 

 aculei remain in the form of small, worn protuberances 

 occupying the said places. Two rows on the back begin 

 just behind the scapular cartilage, the aculei being at 

 first cjuite low, Imt increasing in size as tliev approach 

 the tail, along which the rows proceed parallel to each 

 other, on each side of the median line and nearer to 

 this than to the side-margin of the tail. In these 

 rows the aculei are verj' densely packed, sometimes, 

 as it were, extruding one another. The largest aculei 

 lie in front of the middle of the tail; further back 

 their size again gradually decreases. On the spinal 

 column itself, i)ehind the scapular cartilage and in the 

 caudal region, there is no row of aculei. 



The dorsal side is of a plain yellowish gray, the 

 ventral side of a translucent milky wliite, the muscles 

 of the pectoral fins being visible, and the tips of the 

 fins showing a bluish tinge. According to Montagu the 

 back is of a plain grayish brown; but in one specimen 

 he found a few black spots on this ground-colour. 



The external differences of sex are confined, ac- 

 cording to Fries and Malm, to the ordinary cards of 

 spines on the sides of the head and the outer parts 



