244 
BRITISH ENTOMOSTRACA. 
Linnaeus, in the tenth edition of his ‘ Systema Naturae,’ 
1758, and again in his 'Fauna Suecica/ 2d edit. 1761. 
notices the Argulus under the name of Mono cuius foliaceus , 
In the 12th edition of the 'Systema/ 1767, he unfor- 
tunately, however, confounds it with the Caligus, under the 
name of Monoculus piscinus. Under this name he refers 
to the Argulus, as described by himself, in his two last- 
mentioned works, and by Loefling ; to the Caligus, as 
described by Faster, in his ' Opuscula Subseciva / and to 
the Prosopistoma, figured by Geoffroy, in his ‘ Insectes de 
Paris/ Fabricius, in his ' Systema Entomologiae/ 1775, 
and Gmelin, in the 13th edition of the ' Systema Naturae/ 
repeat this error, giving the species Monoculus piscinus, 
with all the faulty synonyma. Geofiroy, in his ‘ Insectes 
de Paris/ 1762, observing that this, and some other 
species of Entomostraca, had two eyes, formed the genus 
Binoculus to receive them. This little parasite he had 
once found upon the stickleback ; but not having time to 
examine it attentively, he has given no lengthened de- 
scription, merely noticing it under the name of Binoculus 
g aster os tei A* 
Ledermiiller, in his ' Amusements microscopiques/ 
part i, 1764, has given a figure of the Argulus, and de- 
scribes it as "a small aquatic in sect,” which he thought 
worthy of attentive consideration. His figure is enor- 
mously magnified, and very indifferent. Muller is the 
first author who has given it the name of Argulus. In 
his 'Entomostraca/ 1785, he established the genus 
Argulus, and described two species, indicating, besides, a 
third. The last is a very doubtful species, while the two 
first are the same, the only difference being in age, 
Muller erroneously considering the young animal as dis- 
tinct from the adult. 
* The second species of his genus Binoculus he calls Binoculus hcemi- 
sphcericus, and gives as synonyms the references of Frisch, Loefling, and 
Linnseus (10th edit.), to the genus Argulus. An examination of the figure 
accompanying the description distinctly shows, however, that this is a totally 
different animal, being the Prosopistoma of Latreille. 
