156 
SCANDINAVIAN FISHES. 
Fam. C0TT1DJE. 
Body of the typical Cottus-form ( the head thickest and the body conically pointed posteriorly), without cuirass 
most often naked or partly covered with plates or spines. Spinous-rayed part of the dorsal fin shorter {with fewer 
rays) than the soft-rayed part. No spinous rays in the anal fin a . By far the greater part of the rays of the 
pectoral fins, as a rule, simple. Pseudobranch ice present. Vertebrae generally more than 30. 
Subfamily € 0 T T I N M. 
Head more or less completely armed with spines, but not cuirassed. No air-bladder. 
In the fauna of the northern seas the true Cotti and 
their nearest relatives are among the most prominent 
fishes, and their typical form is, therefore, most probably 
well known to most of my readers. “A head which is large 
in proportion to the rest of the body, sharply rounded 
at the top and armed with spines or protuberances, 
and which through the dilatation of the gill-cover and 
the branchiostegal membrane may undergo considerable 
lateral extension and assume a more depressed form; 
and a body which is rounded and tapers posteriorly 
in a conical form, is covered by a naked or spinous, 
highly mucous skin, and bears large, rounded fins - 
these are the general characters which give these fishes 
an easily recognisable, though uninviting appearance”. 
Many of them, though not those forms which are com- 
mon among us, have ciliate scales, scattered or even 
imbricate; but in far the greater number of cases the 
above description of EkstrOm holds good. 
The spinous equipment of the head conforms to 
the same type as in the preceding family, though it is 
generally more highly developed. A pair of nasal spi- 
nes are almost always present; and on the posterior 
part of the head, from the forehead to the end of the 
occiput, is a quadrilateral or harp-shaped patch, which 
is often concave and is bounded at its four corners by 
the so called parietal spines. The spines of the margin 
of the preoperculum are as a rule four in number; 
the operculum and interoperculum are generally armed 
with spines at the hind upper corner, and the sub- 
operculum at the lower corner. As a rule, too, the 
clavicular and supraclavicular bones are furnished with 
spines at the top. The system of the lateral line is 
generally well-developed in these fishes, both on the 
head and on the body — in the former region it is 
most developed in the Four-horned Cottus — and on 
the body there are usually distinct lateral branches of 
the lateral line proper, but apparently 6 the system is 
here developed posteriorly only at an advanced age, 
and often enough the hind portion of the lateral line 
is partly incomplete or even totally wanting on the 
posterior half of the sides. 
Another distinctive point in the Cottidae is the ex- 
ternal difference of sex, which is most often sharply 
marked 1 '. Besides the fact that the females are usually 
more numerous and larger than the males, the latter, 
at least when full-grown, generally have a genital pa- 
pilla at the vent; more marked spinous warts on the 
skin and more highly developed spines on the inside 
of the rays of the pectoral and ventral fins, the latter 
of which are most often elongated; higher dorsal fins; 
and a different coloration, often spotted with white. 
The centre of the geographical distribution of the 
Cottidae — if we disregard their scaly representatives 
in India and Australia — lies in the Arctic and Boreal 
seas: some species, too, are circumpolar. They really 
belong to water of moderate depth where the bottom 
“ Of Hie first ray in the anal fin of Heniilepidotus trachurus, from Kamtchatka Cuv., Val. ( Hist ■ Nat. Poiss., vol. IV, p. 278) say 
that it may possibly be a spinous ray (“pourrait etre epineux”), but in specimens from Behring Island it is distinctly articulated. 
h Cf. Collett, Norcjes Fiske, Vid. Selsk. Forh. Christ. 1874, Tillsegsh., p. 25. 
c Cf. Lutken, Vid. Medd. Naturh. For. Ivbhvn 1876, p. 387. 
