THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



No. 68. FEBRUARY 1843. 



XV. — The Natural History of the British Entoraostraca, 

 No. VI. By W. Baird/M.D., late Surgeon of the 

 H.E.I. C.S. Berwickshire, Member of the Berwickshire 

 Naturahsts' Club, and Assistant in the Zoological Depart- 

 ment of the British Museum. 



[Continued from Ann. Nat. Hist. vol. i. p. 25G.] 

 [With two Plates.] 



The genus Lynceus of Miiller is the second genus of the 

 group Cladocera of Latreille, vide ' Mag. Zool. and Bot.' vol. ii. 

 p. 400. According to Milne Edwards's arrangement it forms 

 the third genus of the Family Daj)hnidiens, Order Clacloceres 

 or Daphndides. It is composed however of rather heteroge- 

 neous elements and requires to be completely reformed. 



Bibliographical history. — Miiller established the genus in 

 his ^Zoolog. Dan. Prodrom.' in 1776, and named it Lynceus 

 from its having, according to h's idea, two eyes. At the time 

 he established it, no author had previously taken notice of 

 any species belonging to it. In 1781 he confirmed the genus 

 in his w ork on the " Entomostraca," described nine species, 

 and gave a few particulars Mith regard to them. About the 

 same time Schrank and Eichhorn both mention an insect, 

 which may perhaps be the same species, and which evidently 

 belongs to this genus. The first of these two authors in his 

 * Enum. Insect. Austriae,' 1781, p. o^Q, no. 1119, describes it 

 briefly as Monoc. injusorius, testa bivalvi, rostratus, oculis duo- 

 bus in rostro sitis, and says it is very abundant in stagnant 

 waters, and is perhaps the smallest of its congeners. Eichhorn 

 gives a figure of his species, says it is distinguished from that 

 " JVasserjioh" described by Schfcffer {Daphnia) in that it has 

 a pointed beak which lies close upon the mouth ; that it differs 

 from it in its motion through the water, not by bounds but 

 swimming like other insects in the water, and that it is very 

 common. Vide ' Beytr. zur Naturgesch.' p. 37. t. iii. f. D. 1 78 1 . 

 These authors give little satisfactory information however 

 with regard to the genus, and Miillei-'s characters are very in- 

 diflferent, as will be more clearly shown hereafter. His spe- 



Ann. ^- Mag. N. Hist. Vol. xi. G 



