516 History of British Entomostraca. 



authors I have already quoted previous to him, were so superficial, 

 that even when illustrated by figures, which are also generally very 

 bad, there was no possibility of distinguishing what species they 

 meant to describe. This difficulty may be readily seen upon in- 

 specting the synonymes given by Muller, and then referring to the 

 authors quoted by him, when we can easily observe that he himself 

 has made several mistakes in such references, neither the descrip- 

 tion nor figures of such agreeing with his. For instance, under the 

 species pubera, he refers to the M. conchaceus of Linnaeus, with the 

 description which that author gives in his Fauna Suecica, " antennis 

 capillaceis, multiplicibus, testa bivalvi,"' — a description so very ge- 

 neral, that it answers equally well to any or all of his eleven species. 

 He also refers to Joblot for the same species, but from the figure 

 which that author gives, as well as from his description, it appears 

 to me, that it much more nearly resembles Muller's Candida, and 

 the reference to De Geer is equally faulty, as it is evident that fi- 

 gure 5 and figures 6, 7 of that author, both of which are quoted by 

 Muller as the pubera, are in reality two distinct species ! In deter- 

 mining the species, therefore, we must consider the researches of the 

 various authors previous to Muller as of little or no use whatever. 

 Indeed after Muller's time the various authors who have taken no- 

 tice of this genus of insects have done little else but copy him, till 

 the appearance of Straus's paper and the work of Jurine. For in- 

 stance, Gmelin in the 13th edition of the " Systema Naturae," 1788, 

 not only quoted Muller's species, but gives his faulty references 

 also ; and Manuel, in his article " Monocli," in the " Encyclope- 

 dic Methodique, Histoire Naturelle, Vol. 7th," 1792, after a few 

 general details, copies the same species as Gmelin gives ; while Fa- 

 bricius in his " Entomologia Systematica," 1793, gives the 11 spe- 

 cies which Muller gives, retaining in addition to this, Gmelin's er- 

 roneous quotations. Bosc, in his " Histoire Naturelle des Crustaces 

 faisant suite a l'edition de Bufifon, publie par Deterville," 1802, 

 gives a great many interesting details of this genus ; as does also 

 Latreille in his " Histoire Naturelle Generale et Particuliere des 

 Crustacees et Insectes, faisant suite a l'edition de Buffon, publie 

 par Sonnini," 1802 ; but he only mentions Muller's species. Ram- 

 dohr in 1805 published his little work on the Monoculi,* in which 

 he gives some very excellent details concerning the anatomy of the 

 Cypris, accompanied by some very good figures, but his work does 

 not seem to have been known to almost any of the succeeding na~ 



* Beytrage zur Naturgescbicte einigen deutschen Monoculus arten. 



