BLUE-MOUTII . 
155 
length". The least depth, on the other hand, is greater 
in the Blue-mouth. In a specimen of this species 352 
mm. long the least depth of the tail is 9 % of the 
length of the body, while in Sebastes we have never 
known it to exceed 8V 2 The length of the head is 
also greater than in the Norway Haddock, being about 
34 % of the length of the body 6 . The eyes of the 
Blue-mouth, too, are comparatively larger — even in 
specimens 350 mm. long the longitudinal diameter of 
the orbit is about 10 % of the length of the body, a 
relation which seems to cease in the Norway Haddock 
at a length of about 225 mm. The dorsal tin is re- 
latively of the same length in both species; but in the 
Blue-mouth the spinous-rayed part is higher and com- 
paratively shorter. The caudal tin is perfectly truncate 
or rounded. The pectoral tins with their singular form 
— superiorly truncate at the point — are considerably 
broader at the base than in the preceding species, and 
their simple, lower rays are thicker and to a great 
extent free at the top, “tingerlike”, a circumstance from 
which the species derives its name (dactyloptera). The 
length of the belly (the distance from the front point- 
in the base of the ventral tins to the beginning of the 
anal tin) is less in this species than in the preceding 
one, being under V 4 of the length of the body. This 
is shown more clearly by comparison with the least- 
depth of the body or the length of the loAver jaw, both 
of which are greater in the Blue-mouth, the former 
being more than x / 3 , the latter more than 3 j i , of the 
length of the belly. 
The connexion between the suborbital ring and 
the preoperculum is much more marked in the Blue- 
mouth than in the Norway Haddock. This “osseous 
bridge” runs externally across the. cheek in the form 
of a sharp ridge, which is anteriorly continued on the 
surface of the preorbital bone. The superior ridges 
and spines of the head are also more strongly defined 
in the Blue-mouth. The least- breadth of the inter- 
orbital space in middle-sized specimens, about 350 mm. 
in length, is only about 12 % of the length of the 
head and 42 % of the longitudinal diameter of the 
orbit. In this narrow interorbital space runs a deep, 
longitudinal groove, coasted by two frontal ridges, which 
in the preceding species are only rudimentary; and 
between the latter and the raised, upper margin of the 
orbit runs another groove on each side. In each of these 
t-wo lateral grooves lies a cranial branch of the lateral 
line, with an orifice, which is sometimes open, above 
the anterior nostril and nearer the middle of the fore- 
head than it, while a similar muciferous pore, the orifice 
of the branch of the system of the lateral line which 
belongs to the inferior orbital margin, appears outside 
and below the anterior nostril c . 
The scales are of the same structure a-s in Sebastes , 
with fine spines' at the hind margin, and within these 
a pretty, retiform brim, formed of the roots of pre- 
existent, marginal spines; but the accessory scales are 
entirely wanting in this species. 
The lateral line slopes fairly evenly down from 
the temples, but never descends so low as the middle 
of the side. 
The geographical range is remarkable in one respect, 
though this may be explained by the variations in the 
depth of the Atlantic. The Blue-mouth is a Mediter- 
ranean fish, by no means rare off Nice and in those parts 
of the Mediterranean where hooks are used for deep-sea 
fishing, and it is also known off the south of Portugal, 
the Canary Islands and Madeira; but north of Portugal 
it has never been found south of Norway, where it 
occurs at depths varying from 100 to 300 fathoms, 
from Stavanger north along the whole coast. It is 
most often taken off Bergen, where it is met with all 
the year round. It- was from here that the specimens 
were obtained which enabled v. Duben and Koeen in 
1844 to claim and describe it as a Scandinavian species; 
but as far north as Tromso, according to Collett, it is 
so common that it is sometimes caught “by the barrel . 
It is a veil knoAvn, say v. Duben and Koeen, to most of 
the Bergen fishermen by the name of Skdr-aur (ur) d or 
BJakdft, the latter name corresponding to Boca-negra 
(Black-mouth), the name by Avhich it is knoAvn in Ma- 
deira. According to Loave its flesh is of little value, 
being both flabby and tasteless. According to Lilljeboeg 
its flavour is not so good as that, of the Nonvay Haddock. 
° In one of the largest specimens (about 440 mm. in length) Steindachner, however, found the greatest depth of the body to be 
only 25 % of the length. 
h According to Steindachner, however, the length of the head varies between 31 % and 33 % of that of the body. 
c Cf. the preceding species. 
d = Rock-ur, cf. the preceding species. 
