318 
SCANDINAVIAN FISHES. 
The jaw-teeth are pointed and fixed, but small and 
sparse, varying from about 20 to 4 or less in either 
jaw. Their number is sometimes the same on each 
side, but they are usually unsymmetrical in this re- 
spect. In the lower jaw they are set on the inside of 
the margin itself, but in the upper jaw, on the other 
hand, further in, on the inside of the intermaxillary 
bones. The vomerine teeth are like the jaw-teeth, but 
still fewer (from 5 to 1) and more irregular in size. 
The outer margin of the upper pharyngeals is furnished 
with similar, but longer teeth, whereas the lower pha- 
ryngeals are toothless. The gill-rakers are short, their 
number on the first branchial arch being 13. 
The oesophagus widens just behind the pharynx, 
and runs straight back to the pylorus (fig. 84), with- 
out forming any distinct stomach; but a short blind 
a 
Fig. 84. Part of the intestinal canal of Tracliypterus arcticus. a: the 
stomach, opened and with the right side folded hack to show the interior; 
b: the pyloric part of the stomach; c: the duodenum or first division of 
the intestine; d, d: the second division of the small intestine; e: the 
pyloric appendages, the openings of which are shown in the section of 
the duodenum; f: the valve at the passage of the small intestine 
into the rectum; g: the rectum, opened; h: the spleen. After Keid. 
sac rises from the end of the pylorus. From the py- 
lorus the first division of the small intestine (duodenum) 
curves straight forward under the oesophagus, sur- 
rounded by extremely well-developed and numerous 
pyloric appendages. Just in front of the anterior end 
of the mass of pyloric appendages the small intestine 
turns back under the former, and in a line with the 
pylorus, where the spleen is also situated, passes into 
the large intestine (rectum), which runs straight back, 
and above the vent, just behind the middle of the body", 
forms a geniculate curve down to the anal opening. 
The course of the lateral line is fairly straight, 
but just behind the head it slopes downwards, and thus 
comes nearer to the bell}'’ than to the back * * 6 . With 
this exception it follows the direction of the spinal 
column, externally showing the position of the latter 
within the body. Each of its plates, at least in spe- 
cimens less than 1 m. in length, may be armed with 
a spine pointing in a forward direction. The spines, 
however, seem as a rule to disappear with age. 
At first sight the Avhole body, with the exception 
of the spines belonging to the lateral line and the dorsal 
fin, is apparently smooth, distinct, verrucose tubercles 
appearing only at the ventral margin. But on closer 
examination the surface of the body proves to be di- 
vided into small squares, consisting of flat tubercles, 
arranged in a kind of mosaic. These tubercles are 
covered by the thin, naked epidermis, which is tin- 
coloured, but has a silvery lustre. The ground-colour 
is diversified by two or three coal-black spots, of the 
same size as the eye or smaller, which are round or 
oblong (in the latter case set obliquely), on the upper 
part of the sides. Two of these spots belong to the 
abdominal part, and the third, which seems to be soon- 
est obliterated during growth, is set on the caudal part 
of the body". The forehead, the top of the snout and 
the tip of the lower jaw are also black. All the fins 
are blood-red. 
The true home of the Dealfish is unquestionably 
in the deeper, if not in the deepest, parts of the North 
Atlantic. Of its manner of life at these depths we 
know nothing. It is only by accident that it can come 
into the hands of man, for our ordinary fishing-tackle 
is useless at depths so great. Like many other deep- 
sea fishes, however, when some fortuitous cause has 
suddenly raised it above the depth where the pressure 
is suitable for its organization, it is borne to the sur- 
face against its will, and then floats helplessly about, 
unable to descend again. But on one or two occasions 
it has shown its capacity of adapting itself to water of 
a less depth: Nilsson states that in Norwegian Fin mark 
“ In the specimen from Vinga the distance between the tip of the snout and the vent is 54 % of the length of the body, excluding 
the caudal fin. According to LUtken this proportion sinks, on an average, with increasing age to 51 %, and may even be as low as 49 °f. 
6 Where the body is deepest, just in front of the vent, in the specimen from Vinga, the distance between the lateral line and the 
ventral margin is 72 / of that between it and the dorsal margin. 
c The distance between the first spot and the tip of the snout is from about 21 to 26 % of the length of the body, and between 
the second spot and the tip of the snout from about 46 to 50 % of the length of the body. In the specimen from Vinga we find a dis- 
tinct trace of a fourth (posterior) spot. 
