348 
SCANDINAVIAN FISHES. 
very beginning of the anal tin, the least depth of the 
body, just in front of the caudal fin, decreasing with 
age, in the specimens mentioned above, 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 
the other parts of the body, in specimens about 200 
mm. long measures 1 / s of the length, but afterwards 
sinks to about 27 % thereof. The greater part of the 
length 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 difference, 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. Both 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; and in the upper jaw the 
teeth in the outermost row 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 
inner (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 been supposed to 
distinguish our Garpike from the Mediterranean form. 
We have learnt, however, from Steindaciiner’s obser- 
vations that the Mediterranean Garpike of this species 
sometimes possesses these vomerine teeth, and Kroner 
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, which 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 young 
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 considerably 
tumid. 
The forehead is flat or only slightly convex, and 
the boundary between 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 
longitudinally than vertically. The sides of the snout 
above the lower jaw are formed chiefly by the trian- 
gular preorbital bones, which, when the mouth is closed, 
cover the lateral branches of the intermaxillary 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 which we have described above, with the 
longest corner pointing in a forward direction. 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 V 5 of the total length of the latter, sub- 
sequently increases to such an extent that it eventually 
measures 1 / i or 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 V 2 that of the 
postorbital part of the head, in shape resembles “a 
quadrant,” as Niesson has happily 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 interoperculum, which forms an elongated triangle, 
growing narrower in front and united by a ligament 
to the angular part of the lower jaw. The gill-openings 
are large and extend forward between the branches of 
the lower jaw to a line with the anterior margin of the 
eye. The branchiostegal membranes, which are generally 
extended on twelve flat, SAVord-like rays, are free, but cross 
each other in front, Avhen the gill-openings are closed. 
In two of the specimens belonging to the Royal Museum these teeth are wanting. 
