120 
Thompson’s midge. 
from Mr. Coucli, and from these the Strangford species differs 
as follows: — My specimens, under eleven lines in length, do 
not, like the Cornish fish, which is one inch five lines long, 
exhibit cirri on either jaw. The ventral fins in mine are 
equal to one fourth of the entire length, in the English specimens 
to about one seventh; in the latter the longest rays have a 
fibrous termination, whereas those fins are somewhat square 
at the end in the Strangford specimens; besides, they are in 
those of a pitchy blackness for the last third of their length, 
although in the other of a uniform pale colour throughout. These 
differences were likewise constant in Cornwall and Strangford 
specimens of similar length.” 
This minute description by Mr. Thompson will render 
unnecessary any further remarks of the same sort derived from 
specimens which I have obtained, and for which I return thanks 
to Mr. Thomas Edwards, of Banff, in ISTorth Britain; who in 
the capture of a single specimen readily discovered that it 
belonged to a species not generally recognised, and who, on 
my enquiring after further particulars, readily procured for 
my use eleven other examples; some considerable advantage 
to science arising from this supply being that it not only 
satisfied me on a close scrutiny that there did not exist any 
barbs where Thompson could not discern them, on the upper 
and under lips, but also that the ventral fins were not situated 
near the throat as that gentleman supposed, but that they 
were placed far back on the belly; and also not in near contact 
with each other. On the point of situation repeated examination 
has compelled me indeed to form a different conclusion from 
that arrived at by Mr. Thompson; but I feel persuaded that 
this difference is to be regarded on his part only as a slip of 
the j)en, and the whole of the other particulars are too much 
alike to admit of a doubt that the Scottish fish and that of 
Ireland are exactly the same. Laid by the side of the true 
Mackarel Midge, the difference between them is conspicuous; 
and the greater length of the ventral fins, with their situation 
and intensely black colour of the hindmost portion were obvious 
in all the specimens. No ciliated membrane could be discovered. 
A later communication from Mr. Edwards confirms the 
remark of Mr. Thompson as regards the surprising agility of 
these fishes; their nhnbleness being such as to render it 
