1080 
SCANDINAVIAN FISHES. 
Chimcera borealis , Shaw, Gener. Zool., vol. V, part. I, p. 365, 
tab. 157. 
Chimcera arctica, Hollb., Bohusl. Fisk., fasc. II, p. 1 cum 
tab. (Gbgs Wett., Witt. Samh. N. Handl., part. IV). 
Chimcera mecliterranea, Risso, Eur. Me'r., tom. Ill, p. 168. 
(?) Chimcera plumb ea, Gill, Proc. Philos. Soc. Washington, Dec. 22, 
1877; vide Jobd., Gilb., Bull. U. S. Nat. Mus., No. 16, p. 54. 
The Northern Chimeera attains a length of about 
a metre". The greater part of this length — 2 / 3 or 
more — is occupied by the prolongated tail 6 , which is 
thread-like at the tip. The greatest depth, just behind 
the pectoral tins, measures 1 / s — 1 f 1 of the length; and 
the greatest breadth (thickness), just in front of the said 
point, is about 1 / 2 — 3 / 5 of the greatest depth. Where 
the first dorsal fin is situated, the dorsal line is straight; 
from this part it slopes at an angle of about 45° to- 
wards the snout, but very slowly towards the tip of 
the tail. The inferior profile of the head ascends from 
behind about as much as the upper profile descends or, 
when the mouth is open, a little more; but the belly 
is usually rounded and tumid, the inferior caudal profile 
(behind the ventral fins) thus ascending in a very gra- 
dual curve. The body is, however, so loose and slippery 
that no constancy in these respects can be expected. 
The length of the head, which is conical and be- 
hind laterally compressed, decreases as usual during 
growth, varying between 15 and 11 % of that of the 
body in specimens 7 — 9 dm. long. Its most charac- 
teristic features, the position of the mouth and nostrils, 
as well as the structure of the soft and somewhat trans- 
lucent. snout, have already been described. The longi- 
tudinal diameter of the large and ovally rounded eyes 
in the specimens just mentioned measures about 1 / 3 
(37 — 31 %), and their vertical diameter about 1 j r> (22 
— 18 %), of the length of the head. They are set high, 
their superior margin lying but slightly below the frontal 
profile, but somewhat obliquely, sloping in a forward 
direction; and whereas the length of the snout in front 
of them measures about l / 2 (48 — 51 %) of the length 
of the head, the postorbital length of the head is not 
much more than 1 / 3 (35 — 38 %) of its entire length. 
The elongated form is not restricted to the orbits, but 
is shared by the pupils. At the anterior margin of 
the eyes the forehead of the females is somewhat tumid, 
and in the males the corresponding prominence is me- 
dially concave; but behind the concavity articulates the 
singular hooked organ (fig. 294, If) whose probable 
function as a prehensile organ during copulation we 
have already pointed out. It is a curved rod of 
hard cartilage, the base of which is widened and pro- 
longated, gliding by means of a longitudinal articulary 
groove on the median edge of the forehead, and the 
top of which is furnished on the under surface with 
a card of 40 — 50 pointed, recurved teeth. As the 
form of the articulary surface shows, the hook is only 
slightly erectile; but when it is depressed, the card 
of teeth works against the anterior part of the said 
prominence. 
On the external surface of the snout the Northern 
Chirmera acquires one of its most characteristic singu- 
larities, consisting in the ramifications of the lateral 
line. The lateral line itself extends, as usual, along 
the sides of the body, in front rather high, behind 
nearer to the middle of the sides, until it descends just 
behind the beginning of the lower caudal lobe to follow 
•the base thereof. It is without true pores, but instead 
has a fissure-like opening throughout its length, this 
being due to the structure of its wall, as first described 
by Leydig 0 . Instead of piercing through scales, which are 
wanting in these fishes, the wall of the lateral line is sup- 
ported by half-rings'* set beside each other and branched 
at the tops. In this form the lateral line advances on 
the head, where it runs upwards and inwards 6 on the 
occiput, and just behind the mouths of the aquceductus 
vestibuli sends out a transverse canal / , a line of commu- 
nication between the two sides of the body, with a 
backward offshoot in the middle. Forward from this 
transverse canal a supraorbital branch 5 ' runs on each 
side of the head, above the eye and laterally along the 
bridge of the snout, to the side of the tip of the snout, 
where it bends downwards and backwards, though only 
to meet and join in a curve on the under surface of the 
snout the supraorbital branch of the opposite side. A 
a Day and Lilljebobg give 4 feet (1,200 mm.). Our largest specimens are females about 95 cm. long. The true length of the 
body is in many cases doubtful, for it is difficult to see whether the tip of the tail is entire or broken. 
6 Our specimens corroborate Lilljebobg’s statement that the males have the comparatively longest tail; but Iyroyer’s measurements 
show the reverse, and rather indicate that young Chimasras have a comparatively longer tail than old. 
c Arch. Anat., Physiol. 1851, p. 251, taf. X, figs. 2 and 9. 
d Of an osseous structure, according to Leydig. 
e This ascending portion is called by Garman (Bull. Mus. Comp. Zool. Plarv. Coll., Cambr., vol. XVII, No. 2) the occipital canal, 
f Aural canal, according to Garman. 
g Cranial canal and rostral canal , according to Garman. 
