348 



SCANDINAVIAN FISHES. 



\eiy beginning of the anal fin, tlie least depth of the 

 body, just in front of the caudal tin, decreasing with 

 age, in the specimens mentioned al)ove, from 35 to 25 

 % of the greatest depth thereof. 



The length of the head, which during early youth 

 is increased by the elongation of the jaws more than 

 tlie other parts of the body, in specimens about 200 

 mm. long measures Vs of the length, but afterwards 

 sinks to about 27 % thereof. The greater part of the 

 lensith of the head is formed, as we have mentioned, by 

 the jaws. The length of the lower jaw may rise to 

 about 27 % of that of the body or 87 % of that of the 

 head, but sinks with age to about 19 % of the former 

 or 73 % of the latter. The upper jaw is invariably the 

 shorter, but the difterence, which in specimens about 

 200 mm. long may be at least 23 % of the length of 

 the lower jaw, is to a certain extent reduced by age, 

 and eventually sinks so low that the length of that part 

 of the under jaw which projects beyond the upper, is 

 only 7 % of the total length thereof. Botli jaws, to 

 the end of the upper, are armed with straight, pointed 

 teeth, consisting partly of large, scattered teeth set in 

 a row and partly of one or more rows of smaller teeth 

 outside this row. In the greater part of the upper jaw 

 and on the hind part of the margin of the lower these 

 teeth form a perfect card; aiid in the upper jaw the 

 teeth in the outermost ro^v point straight outwards. 

 The intermaxillary bones are united throughout their 

 length, and the branches of the lower jaw in the outer 

 (anterior) part for about half their length. On the 

 iinier (upper) side of this coalescent part (in the groove 

 of the lower jaw) there runs along the mesial line of 

 the jaw an osseous ridge forming numerous zigzag turns, 

 which remind us of the enamelled curves in the com- 

 pound teeth of certain mammals. On the head of the 

 vomer there occurs a very inconstant and sometimes 

 entirely absent, oblong card of teeth, narrowing behind 

 to a point, the presence of which has l)een supposed to 

 distinguish our Garpike from the Mediterranean form. 

 We have learnt, however, from Steindachner's obser- 

 vations that the Mediterranean Garpike of this species 

 sometimes possesses these vomerine teeth, and Kroyer 

 had already shown that our Garpike is very often with- 

 out them". As we have mentioned above, the upper 

 jaw is without any trace of lips; but on each side of 

 the lower jaw, starting at the corner of the mouth, 



there hangs a narrow dermal fold, \vliich may some- 

 times, though indistinctly, be traced nearly to the tip 

 of the jaw. The palatal folds, the inner transverse vela, 

 are well-developed in both jaws. The tongue is fleshy, 

 toothless, and obtusely rounded at the tip. In 3^oung 

 specimens the profile of the snout slopes gradually from 

 the forehead itself; but in older ones the base of the 

 upper jaw (the intermaxillary bones) is considerablj' 

 tumid. 



The forehead is flat or only slightly convex, and 

 the boundary l)etween it and the cheeks, which con- 

 verge inferiorly, is sharply marked by a somewhat acute 

 angle. The eyes are set in the same plane as the cheeks 

 and in front of the perpendicular from the articulation 

 of the lower jaw. Their diameter is somewhat greater 

 longitudinall}' than vertically. The sides of the snout 

 above the lower jaw are formed chiefly by the trian- 

 gular preorbital bones, ^vhich, when the mouth is closed, 

 cover the lateral branches of the intermaxillar)' bones 

 and the maxillary bones, which are respectively united 

 to the latter. Above the preorbital bone, on each side 

 of the snout, lies the triangular nostril, the singular 

 structure of Avdiich we have described above, with the 

 longest corner pointing in a forward dii-ection. The 

 white, transverse ridge is parallel to the hind side of 

 the cavity. The postorbital part of the head, which, at 

 the end of the singular alterations during youth, mea- 

 sures about ^/^ of the total length of the latter, sub- 

 sequently increases to such an extent that it eventuall}' 

 measures 7* oi" even 27 % thereof. The thin hind 

 margin of the preoperculum is rectangular or even acute- 

 angled, with the lower posterior corner rounded. The 

 operculum, the length of which is about ^/g that of the 

 postorbital part of the head, in shape resembles "a 

 quadrant," as Nilsson has happilv observed; and outside 

 (below and behind) this quadrant comes the falciform 

 suboperculum, with the point situated at the upper cor- 

 ner of the gill-opening and the base touching the base 

 of the interoperculuni, which forms an elongated triangle, 

 gi'owing narrower in front and united by a ligament 

 to the angular part of the lo^ver ja-\v. The gill-openings 

 are large and extend forward lietween the branches of 

 the lower jaw to a line with the anterior margin of the 

 eye. The branchiostegal menibranes, which are generally 

 extended on twelve flat, sword-like rays, are free, but cross 

 each other in front, when the gill-openings are closed. 



" In two of the specimens belonging to the Royal Museum these teeth nre ^vanting. 



