258 BRITISH ENTOMOSTRACA. 



as consisting of two kinds, differing either in sex or 

 species, the one having two antennce looiger than the hody, 

 and the other having none. Strom again, in the ' Skrifter 

 Kiobenhavnske Selskab,' 1770, describes and figures an- 

 other species, and evidently a second time mistakes the 

 tail for the head. 



In describing the Argulns, I have mentioned that 

 Linnseus, in his twelfth edition of the * Syst. Nat.,' con- 

 founded that animal with the Caligus. In the 'Fauna 

 Suecica' he described them as separate species ; but in 

 this latter work he not only quotes his own previous de- 

 scription of the Argulns 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 ' Systema Entomo- 

 logiae,' 1775, and by Gmelin, in his edition of the ' Systema 

 Naturae,' 1788. Slabber, however, previous to Gmelin's 

 edition, in his ' Naturkundige verlustigingen/ 1778, had 

 given a figure, under the name of Oniscus lutosiis, 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 ' Fauna Groenlandica,' 1780, and the latter in the 

 'Berlin Gesellschaft Skrifter,' 1780 and 1782, are accom- 

 panied, especially the latter, with a number of details, and 

 are pretty accurately described by both. Miiller, in his 

 ' Prodrom. Zoologiae Danicaj,' 1776, introduces the genus 

 under the name of " Binoculus," adopting that name 

 from GeofFroy ; but in his ' 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- 



