DAPHNIAD.E. 65 



as his D. si-ma, but which Straus says is not so, but is his 

 D. macrocopifs. The figures which Joblot gives are very 

 indifferent, and it is not easy to say Avhat species they are 

 meant to represent. 



Schceffer, in his Memoir ' Die griinen Arm -Poly pen die 

 geschwanzten mid un geschwanzten zackiger Wasserflohe,' 

 1755, describes at great length two or three species, under 

 the name of Geschwanzten zackiger Wasserfloh, and Un- 

 (jeschwanzten zackiger Wasserfloh, or water-flea with a tail, 

 and water-flea without a tail; and this memoir is the first 

 in which an attempt is made to distinguish different 

 species, the various authors whom I have quoted above, 

 having all, with perhaps the exception of Joblot, described 

 only one and the same. He figures two species, the 

 D. pulex and siwa, and gives a sketch of the head only of 

 a third, which, being provided with a tail, has been quoted 

 by Miiller and Straus as the I), longispina. This memoir 

 contains a great deal of very interesting information with 

 regard to these little creatures, and having been partly 

 translated into French by Jurine, at the end of his work 

 on the Monoculi, it has become more available to the 

 naturalist. In his ' Icones Insectorum circa Ratisboniam 

 indiginorum,' L766, the same author figures the D. pulex 

 under the name of " Branchipus conchiformis primus," 

 and in his ' Elementa Entomologica,' published in the 

 same year, I believe, he again figures it under the name of 

 " Branchipus conchiformis." 



Poda, in his ' Insecta Musaei Graecensis,' 1761, de- 

 scribes shortly the same species, under Linnaeus' s name, 

 Monocuhs pulex, and Lederm tiller, in his 'Mikroskopischen 

 Gemiiths und Augen-ergotzung,' 1763, gives an in- 

 different figure of a species, which however is easily 

 recognisable as the same. 



Geoffrey, in his '.Hist, abreg. des Insectes,' 1764, 

 gives a good many details of this genus generally, and 

 describes a species under the name of " Perroquet d'eau," 

 which Miiller quotes as his quadrangula, but which Straus, 

 I think more correctly, considers the pulex. 



5 



