84 
SCANDINAVIAN FISHES. 
often occur in shoals, wandering at the surface out at 
sea or along the coast, they are of great importance to 
the fisherman. Their economical value, however, is far 
less than that of the true Mackerels. Only one species 
belongs to the Scandinavian Fauna. 
Genus CARANX. 
The lateral line proper armoured, at least in part. ' 
sides. A spine starts, in a forward direction from the 
ray in the anti 
All the (Jar any idee furnished with scales, which, 
like the Sticklebacks, have the lateral line wholly or in 
part covered with plates, — the form of which strongly 
reminds us of the high scales we have seen in the 
Bramoids — are so closely related to each other that 
with Gunther we may well unite them into one single 
genus. The variety of form — about 80 species are 
more or less known — may induce us, it is true, to 
search for subdivisions within this genus. Such divi- 
sions have been proposed, grounded partly on the dif- 
ferent extent of the armour on the lateral line, partly 
on the breaking-up of the posterior parts of the dorsal 
and anal fins into small, separate fins which occurs in 
some species. Both these differences, however, are met 
with as changes due to age in forms so closely allied 
in other respects that the assumption of a generic di- 
stinction appears unnatural. Lutken", too, though he 
still adopted the genus Trachurus as distinct from 
Caranx, writes as follows: — “At a certain age (at a 
length of 17 mm.) only the posterior half of the lateral 
line is distinct, and one might more readily suppose 
the young specimen before him to belong to Caranx 
than to Trachurus .” True, the same remark applies 
to the covering of scales, which is absent in the fry; 
but in addition to this lack of scales we find in G all- 
id ithys so striking a development in the high form of 
the body and so great a reduction of the first dorsal 
fin that we may well follow Lutken and designate 
these forms by a special generic name, pointing to 
their importance as intermediate forms between Caranx 
and Selene. 
In Caranx the system of the lateral line shows so 
high a degree of development as to place it on a level 
with or even above this system in Cantharus. From 
the arcuate canal in the posttemporal region (above 
the gill-cover and the upper corner of the gill-opening) 
° Spol. Atl., 1. c., p. 536, on Trachurus Cuvieri. 
b This membrane, it is well known, does not contain fat, but 
presence of which round the mueiferous canals of fishes has already b( 
The other scales on the body cycloid. Tail keeled on the 
fourth, interneural bone , which supports the first, spinous 
rior dorsal fin. 
which is continued without interruption by the lateral 
line proper, anteriorly there start two branches. The 
one as usual follows the outer edge of the preoperculum 
downwards and sends out its numerous lateral branches 
with small pores in the ‘adipose membrane’ which 
covers the broad margin of the preoperculum, and is 
continued on the lower side of the lower jaw. The 
other branch of the temporal canal advances towards 
the posterior orbital margin but divides into two, the 
one being continued forward above the eye to its 
middle point, the other belonging to the suborbital 
ring and, together with its many small branches in a 
downward direction, covered by the ‘adipose membrane’ 6 
which lies over the posterior and anterior portions of 
the eye. These small branches and pores are, as usual, 
most distinct on the preorbital bone. From the tem- 
poral canal there also starts the ordinary upward branch 
towards the occiput, but in this case the most impor- 
tant continuation of the latter is the dorsal canal (the 
dorsal lateral line), which runs along the base of the 
dorsal fins, often right to the end of the posterior one. 
From the bow which forms the connection between 
this dorsal canal and the temporal one, there starts 
backwards, from the concave side of the bow, a smaller 
canal between the dorsal one and the lateral line pro- 
per, but nearer the former; and forwards, from the 
convex side of the bow, run the ordinary canal from 
the mastoid region, continued on the side of the fore- 
head to the nasal region, and also another, smaller 
canal in the supraoccipital region as far as the inter- 
orbital space, where it meets the corresponding canal 
of the opposite side and united with this is continued 
along the middle of the forehead as far as the anterior 
orbital margin. In Caranx trachurus all these divisions 
of the system of the lateral line have transverse bran- 
ches at right angles to them, which in their turn send 
is a hyaline (gelatinous) connective tissue (“ Gallertgewebe” , Leydig) the 
en remarked by Leydig ( Lelirbuch der Ilistologie, p. 24). 
