120 thoivipson's midge. 



from Mr. Couch, and from these the Strangford species diifers 

 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 North Britain; who in 

 the caj)ture 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 sujajDosed, 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 j)art only as a slip of 

 the pen, 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 liindmost 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; theu* nimbleness being such as to render it 



