258 
BRITISH ENT0M0STRACA. 
as consisting of two kinds, differing either in sex or 
species, the one having two antennae longer than the body , 
and the other having none. Strom again, in the 4 Skrifter 
Kiobenhavnske Selskab/ 1770, describes and figures an- 
other species, and evidently a second time mistakes the 
tail for the head. 
In describing the Argulus, I have mentioned that 
Linnaeus, in his twelfth edition of the £ Syst. Nat./ con- 
founded that animal with the Caligus. In the 4 Fauna 
Suecica’ he described them as separate species; but in 
this latter work he not only quotes his own previous de- 
scription of the Argulus as a synonym for the Caligus, 
but he even refers to Loefling's figure of that animal as 
further evidence of their identity. This erroneous syno- 
nymy is repeated by Fabricius, in his 4 Sy sterna Entomo- 
logise/ 1775, andbyGmelin, in his edition of the 4 Systema 
Naturae/ 1788. Slabber, however, previous to Gmelin’s 
edition, in his 4 Naturkundige verlustigingen/ 1778, had 
given a figure, under the name of Oniscus lutosus , of a 
species belonging to this family, and delineated the true 
antennae and some other parts very correctly. 
O. Fabricius and Herbst seem also to have better 
understood the anatomy of the animals belonging to this 
group. The species which they have described, the former 
in the 4 Fauna Grcenlandica/ 1780, and the latter in the 
4 Berlin Gesellschaft Skrifter/ 1780 and 1782, are accom- 
panied, especially the latter, with a number of details, and 
are pretty accurately described by both. Muller, in his 
4 Prodrom. Zoologiae Danicse/ 1776, introduces the genus 
under the name of 4C Binoculus,” adopting that name 
from Geoffroy ; but in his 4 Entomostraca/ 1785, he founds 
the genus Caligus. Hitherto no zoologist had clearly 
ascertained the situation of the eyes, and it was from this 
apparent blindness that the generic name was suggested 
to him. With regard to their exact situation, however, 
even he was deceived, for though he really saw the true 
eyes, he yet did not consider them to be such, but 
absolutely mistook a different part altogether. Notwith- 
