226 



SCANDINAVIAN FISHES. 



the length, and in specimens about 270 ram. long 

 about 5"6 %. From the occiput to the vent the body, 

 which is almost terete, is of uniform depth as well; 

 but behind this point it becomes more and more com- 

 ))ressed, even knife-shaped, and also gradually dimi- 

 nishes in depth to the base of the caudal fin, where 

 the de])th of the l)ody is about 2 % of the length. 

 The licad is fairly short in proportion to the length 

 of the ])od\-; but its relative length varies considerably 

 according to age: in specimens 50 mm. long, according 

 to CoLLETT, the length of the head is about \% % of 

 that of the l)ody; in specimens 154 mm. long it has 

 proved to be 13"6 %; in specimens 271 mm. long ITS 

 %\ and in specimens 320 mm. in length, according to 

 CoLLETT, 9*7 %. The occiput is convex, the forehead 

 somewhat compressed, and the superior profile of the 

 liead slightly curved, with the snout sloping more 

 steeply. The gape is only slightly turned upwards, 

 almost horizontal, and the snout projects slightly beyond 

 the under-jaw. The eyes are fairly large, the longi- 

 tudinal diameter being 24 or 23 % of the length of 

 the head. There seem to l^e three pairs of nostrils, 

 two of which, however, are very small, simple openings, 

 most resembling the pores of the lateral line, the an- 

 terior pair being situated just behind the articulation 

 kni)bs of the maxillary bones, and the posterior in front 

 of the anterior upper corner of tlie eye on each side. 

 Between these two o])enings on each side we find a 

 fairlv large, tubular papilla, which should jjrobably be 

 regarded as the true nostril". The maxillary bones 

 are rather short, and some\vhat wider posteriorly than 

 in front. Their length is from 22 to 28 % of that of 

 tlie head. The intermaxillary bones, on the other hand, 

 are narrow, but with fairly large nasal processes. The 

 upper jaw, however, admits of scared)' anj' protrusion. 

 The intermaxillary teeth are small and cardiform, l)ut 

 in the outer row there are several teetli of larger size 

 than the others. The lower jaw-teeth are set in one 

 row, or anteriorly in two. The palatine bones and 

 vomer, as well as the tongue, which is rounded, are 

 without teeth. Beneath the point of the chin a knob, 

 which increases in size with age. The operculum and 



suboperculum, together with the posterior dermal flap, 

 foi-m a triangle, the base of Avhich is about half the 

 distance from the point of tlie flap, Avhich fits into the 

 upper corner of the axil, to the hind margin of the 

 eye. Tlie branchiostegal membranes are entirely free 

 from each other, and are not united to the isthmus 

 until they reach its front pait. There are six, acinaci- 

 forin branchiostegal raj'S, the first of ^vhich is extra- 

 ordinarily small. 



The scales are small, and at the middle of the 

 body, on the upper lialf of the sides, above the lateral 

 line, 18 scales may be counted in a transverse row. 

 The scales Avhich cover the tumid (muscular) cheeks, 

 are still smaller. The system of the lateral line is 

 most highly developed on the head, but even there the 

 pores are generally distinct only in the ro^\' which runs 

 along the hind margin of the preoperculum, and from 

 this point downwards on the lower side of the branches 

 of the under-jaw'. The pores of the lateral line of the 

 body are scarcely distinguishable, but the line runs in 

 a groove straiglit along the middle of the sides. 



The vent lies a little behind the end of the first 

 third of the bod v. In accordance with the changes of 

 growth mentioned above it is relatively situated farther 

 forward in old specimens than in young. In a- speci- 

 men 154 mm. Ions; the distance from the vent to the 

 tip of the snout is 37'7 % of the length of the bod)', 

 in another, 230 mm. in length, 35'7 %. 



The pectoral fins seem pointed, when folded; 

 but, when expanded, they prove oval, with evenly 

 rounded margin. Their relative length diminishes with 

 age: while the length of the body increases from 150 

 to 270 mm., the length of these fins deci-eases from 10 

 to 7'/\, % of that length; but while the length of the 

 body increases from 150 to 230 mm., the length of 

 these fins relatively to the length of the belly between 

 the insertion of the ventral fins and the beginning of 

 the anal fin, suffers 1:)ut very little change, measuring 

 about 40 % thereof. All the rays are articulated, and 

 all, except the first (uppermost) may be branched; 

 sometimes, however, the last (lowest) ray is also simple. 

 The ventral fins are pointed, and, in young specimens 



" Cf. Stuwitz, KBOVErt and Lii.ljeboug. The lulmlar structure of tliis papilla is generally more easily distinguished iu Tjumpenus 

 Fabricii. In the Sharp-tailed Lumpenus it is, in njost cases, difficult to find any opening at the top of the papilla. 



'' The system of the lateral line on the liead is most distinct in young specimens, especially in Lmnpenns Fabricii, where a row of 

 pores lies in a furrow on each side of the temporal region, from the articulation of the preoperculum to the eye. The preopercular row of 

 pores runs from the end of this furrow, in a downward direction, and, from its beginning, the row belonging to the suborbital ring, is con- 

 tinued forward on the snout, along the lower margin of the preorbital bone. In this species, the lateral line of the body, anteriorly at least, 

 is furnished with distinct pores. 



