FIVE-BEARDED ROCKRING. 
555 
posterior nostrils are set nearer to the eyes or at least 
half-way between the latter and the nasal barbels, and 
their anterior margin is usually raised into a semicir- 
cular dermal flap. The mouth is comparatively small, 
and the teeth are blunter than in the preceding species 
and of more uniform size, the inner row in the lower 
jaw being generally the only one distinguished by some- 
what larger teeth. The breadth in the palate of the 
vomerine card of teeth is always less than the longi- 
tudinal diameter of the eyes. The two rostral barbels, 
which this species possesses in common with the North- 
ern Roclding, are well separated from each other, but 
the distance between them is less than their length. 
At the lower margin of the snout (the lower preorbital 
margin), on each side of these barbels, we find here, 
as in many specimens of the preceding species, sinuous 
contractions, the spaces between which remind us of the 
rudimentary barbels in the Northern Rockling. The 
scales are small but dense, and extend, as in the pre- 
ceding forms, out over the pectoral fins and the ver- 
tical fins, especially the caudal. The light-coloured 
pores of the lateral line are in most cases rather in- 
distinct, a.s in the rest of the genus, and the lateral 
line often seems to be interrupted in its curved part, 
below the anterior part of the second dorsal fin. Where 
we have found this line most nearly perfect, it has 
contained 22 pores, arranged thus: 
1st — -7th 
8th 
9th — 22nd 
The relation between this species and the preced- 
ing ones is shown most clearly, however, in the fol- 
lowing table of measurements: 
0 n o s m u s t e l a. 
Length, of the body expressed in millimetres 
Length of the head in % of the length of the body 
Longitudinal diameter of the eyes. „ „ „ „ ,, ,, „ „ 
Least breadth of the iuterorbital space - ,, „ ,, „ ,, „ ,, „ 
Length of the upper jaw „ „ „ „ „ ,, „ „ 
,, ,, ,, lower ,, ,, ,, ,, ,, ,, ., ,, ,, 
Postorbital length of the head „ „ „ „ ,, ,, ,, „ 
Distance between the first dorsal fin and the tip of the snout „ ,, „ „ ,, ,, „ „ 
,, ,, ,, second ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, ,, 
Base of the first dorsal fin „ „ ,, „ „ „ „ „ 
?> ») second ,, ,, — ,, ,, ,, ,, ,, ,, ,, ,, 
Length of the first ray of the first dorsal fin „ „ ,, „ „ „ „ „ 
„ „ „ longest „ „ „ second „ „ „ „ „ „ „ „ „ „ 
„ „ „ pectoral fins „ „ „ „ „ „ „ 
„ „ „ ventral „ — -- „ „ „ „ „ „ „ „ 
Distance between the ventral fins and the beginning of the anal fin ,, „ „ „ „ „ „ „ 
„ „ „ anal fin „ „ tip of the snout „ ,, ,, ,, „ „ ,, „ 
Base of the anal fin „ „ „ „ „ „ ,, „ 
Longest ray of the anal fin — „ „ „ „ „ „ „ ,, 
Least depth of the tail „ ,, „ „ „ ,, „ „ 
Length of the middle rays of the caudal fin „ „ „ ,, „ „ „ „ 
Depth of the body at the beginning of the anal fin „ „ ,, „ ,, „ „ „ 
Greatest breadth of the head „ „ „ „ „ „ „ „ 
A young spe- 
cimen from 
Bohusliin, 
Dec., 1836. 
Average in 
5 specimens 
from Bohus- 
liin, between 
111 and 248 
mm. long. 
80 
191 
22.5 
17.8 
2.9 
2.5 
4.3 
5.0 
11.3 
7.4 
9.3 
8.2 
13.8 
11.1 
20.4 
1(3.7 
32.0 
30.4 
9.5 
11.1 
52.8 
54.8 
5.0 
4.8 
— 
7.4 
12.4 
11. G 
13.7 
_ 11.0 
24.5 
27.4 
41.5 
41.i 
40.8 
43.8 
8.2 
G.g 
5.4 
6.6 
10.o 
10. o 
12. « 
14.7 
11.3 
10.4 
Thus, iu the Five-Bearded Rockling the length of 
the lower jaw and (as a rule) of the upper is less than 
half that of the head; and in all the older specimens 
(more than 1 dm. long) the former is less than 9 %, 
the latter less than 8 %, of the length of the body. 
In these respects the Five-Bearcled Rockling differs from 
all the other Scandinavian species of the genus. Iu 
the young specimen, however, the length of the lower 
jaw in proportion to that of the body falls within the 
limits of individual variation in the Four-Bearded Rock- 
ling; and the length of the upper jaw (from the tip 
of the snout to the hind extremity of the maxillary 
bones) corresponds in this relation to the averages both 
in the three-bearded and the four-bearded species. In 
