FIVE-BEARDED ROCKLING. 
557 
side of the base of the anal tin, is an evanescent for- 
mation. In fall-grown specimens we now and then find 
these carina3 replaced by longitudinal grooves. They 
seem to be most nearly represented in the family Am - 
modytidce, of which fishes we are also strongly reminded 
by the coloration and the silvery white, naked skin. 
Idle truncate or even somewhat, though only slightly, 
concave caudal tin, contrasted with its sharply rounded 
form in adult specimens, also reminds us of the Am- 
modytoids. Even in young specimens 41 mm. in length, 
however, we may find the coloration of the adult spe- 
cimens almost perfectly represented, though a steel-blue 
longitudinal band is still present as a trace of the ori- 
ginal boundary between the colours of the back and of 
the sides. A specimen of this kind, which is preserved 
in the Royal Museum, was taken, together with a 
number of others between 25 and 42 mm. long, all 
in Couchia- dress, by Fisherman Tobias Andersson, on 
the fishing-bank N.W. of Bergen, where the depth of 
water was about 150 fathoms. In this specimen the 
length of the head is 20'5 %, the longitudinal diameter 
of the eyes 4'6 %, the breadth of the interorbital space 
5'1 %, the length of the upper jaw 9'7 %, of the lower 
jaw 10 % , the postorbital length of the head 11 '9 %, 
the depth of the body at the beginning of the anal fin 
1 4*6 and the least depth of the tail 4’9 %, of the 
length of the body. The specimen can hardly be re- 
ferred, therefore, to Onos septentrionalis, though three 
tubercular swellings appear at the lower preorbital 
margin on each side of the slightly more developed 
rostral barbels. Among the barbels the rostral ones 
are developed last, though the length of the body at 
this period varies considerably, but generally measures 
about 21 mm., at which time the breadth of the inter- 
orbital space may already be greater than the longi- 
tudinal diameter of the eyes, though as a rule it is 
less. Not until the rostral barbels are developed, though 
they may still have the form of small, terete protuber- 
ances, can we distinguish this species with certainty 
from the preceding one. 
The internal organs of the Five-Bearded Rockling 
resemble those of the preceding forms in all essential 
respects; but the few (8 — 10) pyloric appendages are 
still longer, and their tips lie rather near the vent. The 
air-bladder is wanting. The peritoneum, the inside of 
the mouth, and the walls of the pharynx are white. 
Onos mustela is an East Atlantic species, with range 
extending from the extreme north of Norway — where 
it has been found, according to Collett, in Ox Fjord 
— and from Iceland (Faber) southwards at least to the 
north-west of Spain (Steindaciiner) and Portugal (Lowe, 
in the British Museum). Great Britain thus seems to 
be the centre of its range; and to all appearances it 
is on the British coasts that the Five-Bearded Rockling 
is commonest. The secluded haunts frequented by the 
adult specimens render this species, like the other spe- 
cies of the genus, hard to find, except when it is left 
behind in pools, under stones etc., by the ebb-tide, and 
it is caught only by accident when the fisherman is 
engaged in fishing for other species. It is, therefore, 
difficult to decide how rare or common the species is; 
but, while English naturalists state that it is common 
on the British coast, the information on this point from 
Scandinavia is less definite. Even in Strom’s time the 
species was known off Sondmor", but Collett does not 
regard it as plentiful on the coast of Norway, though 
he points out that the large numbers in which the fry 
sometimes appear at the surface, seem to show the 
contrary. In Bohuslan the species has received a spe- 
cial name ( Permuclc ), and is, therefore, well-known to 
the fishermen — - Ekstrom, Nilsson, and Malm state 
that it is common there — but ITollberg described it 
as rather rare, and in recent times the Royal Museum 
has had very great difficulty in procuring specimens 
thence. According to Kroyer it is also “extremelv 
rare” in the north of the Cattegat. Schagerstrom found 
/ 
it rare in the Sound. In the Baltic it has never been 
met with. 
In its adult state the Five-Bearded Rockling seems 
to prefer a rocky bottom, but is also found on sandy 
ground, when this is firm and studded with tufts 
of seaweed. It belongs to the littoral fishes, and, so 
far as is known, does not descend into deep water, 
beyond the limits to which the green algm extend. 
Thus it is often met with between the tide-marks; and 
on the coast of Iceland, after the storms of winter, 
Faber saw hundreds of specimens that had been cast 
ashore by the waves to furnish a dainty meal to the 
ravens and seagulls. Malm assumes that on the coast 
of Bohuslan this species is commonest at a depth of 
8 — 12 fathoms; while the Royal Museum possesses se- 
veral specimens taken at less depths, but one from a 
Beskr . Sondm ., pt. I, p. 314: Det andet Slags Tang - Brosme . 
