INTRODUCTION. 
3 
memoir, the arranging them into distinct genera, many 
important and exceedingly interesting details regard- 
ing them never before made known, and the addition 
of a great number of new species which that zealous 
naturalist discovered in the fresh waters and on the sea 
coast of Denmark and Norway. He may be called the 
first regular historian of these animals. To him it is we 
owe a great deal of our knowledge respecting them, and 
to his eloquent descriptions is perhaps owing the further 
researches and more detailed histories of succeeding writers. 
His work on the Entomostraca, published in 1785,* 
though it contains several errors which have been pointed 
out by later waiters, is still one of the most interesting 
memoirs in natural history that we are acquainted with. 
Since the time of Muller much has been done by our 
continental neighbours to add to our knowledge of these 
interesting little creatures, and their individual labours 
we shall take particular notice of as we proceed with this 
work. It is curious, however, that scarcely any British 
naturalist, with the exception of Dr. Leach, has paid the 
least attention to the Entomostraca. His memoirs are 
scattered over a variety of publications, and a great por- 
tion of his attention was directed to the history of the 
parasitic animals belonging to the group. It surely is 
not from want of interest belonging to them, that the 
naturalists of this country have so neglected these curious 
little animals, for many of them are worthy of all admira- 
tion. “The multifarious and complicated structure of 
their body,” says Muller, in his admirable work; “the 
wonderful agility of their members ; the very great fine- 
ness of their organs ; their singular method of living, and 
copulating ; their living in waters which our cattle and we 
ourselves are daily drinking ; the evils which they may 
give rise to, and which are seen to be inflicted upon 
fishes; the advantages, although we are in the greater 
* Entomostraca, seu insecta testacea, quse in aquis Daniae et Norvegise 
reperit, descripsit, et Iconibus illustravit Otho Ereaericus Miiller. Lipsiae 
et Havnise, 1785. 
