PLATE LIV. 
Petromyzon fluviatilis varies greatly in respect of colour. The belly 
is commonly silvery : the sides rather darker, and sometimes yellow, 
finely glossed with gold : the back dusky, blueish, blackish, or ob- 
scurely streaked ; and the fins brown, sometimes violet, sometimes 
sanguineous. Lacepede describes several analogous species that are 
found in the rivers of France. One in particular that approaches 
very nearly to the young of this ; and were it not for the rounded 
instead of angulated form of the dorsal fins, we might be inclined 
to think it rather a variety than a distinct species. The kind alluded 
to is called by Lacepede, Petromyzon septceil, and is described as 
being six or seven inches long, the colour greyish lead colour, and 
all the lower parts or a yellowish white. It is found in abundance 
in the Seine, and rivers flowing into that water. 
Tfie lesser Lamprey inhabits various parts of Europe, but is no 
where more frequent than in Prussia, and some of the states of the 
German empire, especially in Silesia, Pomerania, and the marsh of 
Brandenburgh. The rivers of France produce it likewise, although 
in less abundance. According to Gmelin, it is found in the lakes of 
Japan, and South Ac rifca, as well as those of Europe. In England 
this fish is more abundant in the Thames, than any other river. 
Mr. Pennant speaks of this sort being caught in vast quantities, by 
the fishermen in the vicinity of Mortlake, to be sold to the Dutch 
as bait for their cod and turbot fisheries *. The larger ones are 
“ Above 450,000 have been sold in a season for forty shillings per thousand Of 
late, about 100.000 have been sent to Harwich for the same purpose. It is said the 
Dutch have the secret of preserving them till the Turbet fishery.” Penn. Brit. Zool. 
If we are not misinformed, these are taken much less abundantly, than in the tune of 
Mr. Pennant. The demand for them has dselined some'year*. 
