392 Mr Yarr ell's History of British Fishes. 
" During the early part of the season, the salmon appear to ascend 
only as far as the river is influenced by the tide, advancing with 
the flood, and generally retiring with the ebb." Many salmon as- 
cend during spring ; in the Tweed, for instance, thirty or thirty- 
five miles, and are taken at that distance from the sea clear and 
silvery, and in full condition, in the months of February and March. 
There is, also, undoubtedly, a species omitted, which, though mi- 
gratory, ascends but little way up the fresh water, and which, with 
its provincial name of salmon trout, has done much towards confu- 
sion.* (S. trutta and this have to be separated, and we would re- 
commend, to determine the characters, and then fix the synonyms; 
the reverse has hitherto been the common course pursued. Mr Yar- 
rell has, we think, satisfactorily made out two species of Char ; the 
one from the lakes of northern England and Scotland, the other 
from Wales. Of the Coregoni no figure of Mr Thompson's Pollan, 
C. pollan, is given, and we refer to our own page, 247, for its more 
detailed description. We strongly suspect that this fish is identical 
with the powan of Lochlomond and some others of our Scotch lochs. 
Have we any authenticated instance of the gwiniad occurring in 
Scotland ? Clupeada:. The scaling of the herring is surely re- 
presented much too large. This fish takes the artificial fly readily, 
and is thus caught in the Western Highlands in considerable num- 
bers. The account of the Pilchard from the Couch MSS. will be 
found very interesting. Raniceps trifurcatus is now found to be 
not so rare as it was formerly accounted ; many instances of its oc- 
currence in various seas having been lately noticed. t A tolerable 
figure of this fish occurs in Muller's Zoologica Danica, under the 
name of Blennius raninus, which seems to have been overlooked by 
both Yarrell and Jenyns. Among the Pleuronectidce it may be re- 
marked, that many species select some particular shell-fish for food ; 
thus the Dab was noticed long ago by Peter Colin son to feed on 
the Pecten obsoletus, a fact since confirmed by Dr Johnston, who 
informs us, " that he has rarely opened a specimen without finding 
the stomach full of this pretty shell," The Platessa microcephala 
again feeds much on Chitons, while the clam is seldom found in it. 
Mr Yarrell describes four species of eels, three of them very dis- 
tinctly marked ; and we can only account for their remaining so 
* The Salmon Trout at Berwick is the young of S. eriox, quite a different 
fish from that now alluded to. 
f See a paper in the present number on R. trifurcatus, page 344. 
