OBSERVED IN THE NOUTH FOLAB SEA. 519 
for its reception, — a distinction which it well merits, as the 
want of an adipose fin, exclusive of differences in internal 
structure, keep it separate from the already heterogeneous 
Linnaean genus Salmo ; and its organisation renders it 
equally unfit to unite with Esocc-^ the only other genus with 
which it has any affinity. 
Shape. -^'SN hen viewed laterally, the outline of the fish, 
exclusive of the tail, is nearly oval, the curvature of the 
belly being a little greater than that of the back. The tail 
lies nearer the plane of the back than of the belly, and is 
much narrower than the body ; hence it is connected at the 
anus with the curve of the belly by a sudden and very con- 
siderable slope, the whole of which is occupied by the anal 
fin. The body is greatly compressed. Its greatest thick- 
ness is just above the lateral line, or near the back. The 
belly has a very acute edge, free from serratures; the back 
is also acute, but in a less degree. 
The lateral line lies nearer to the back than to the belly. 
It continues straight from the operculum till it passes the 
dorsal fin^ when it is slightly deflected. 
Colour. — The body has a silvery colour, with much 
lustre. 
The scales are irregularly orbicular, and large, being 
about half an inch in diameter. The membrane that covers 
their bases has a bluish-grey colour. 
The head is much compressed, and sideways appears 
conical, with an obtuse snout. There are no scales on the 
vertex, but the occiput is covered with a large scale on each 
side. The irides and sides of the head are tinged with 
honey-yellow, and have much nacry lustre. The infra- 
orbitar bones have in the aggregate a nearly circular out- 
* Hiodon, Le Sueur, ' Journal of Academy of Sciences, Philadelphia,' 
vol. i. p. 367. tab. 14. 
