DEC 30 1897 



Article III. — The Xorth American Species of Diaptomns. 

 By Frederick William Schacht. 



INTRODUCTION. 



The first published reference to that group of genera of 

 Entomostraca now known under the family name of Centro- 

 pxKjiihe is contained in 0. F. Miiller's "Entomostraca sen 

 Insecta testacea quae in aquis Daniae et Norvegiae reperit," 

 etc., published at Frankfort-on-the-Main in 1785, in which 

 paper certain copepod species now included under the genus 

 Diaptomus were treated under the general name of Cyclops. 

 Species of Diaptomus were later described by Jurine ('20) 

 under Moiiociilits, but the genus Diaptomus was first estab- 

 lished by Westwood ('36). Various names have since been 

 applied more or less closely to the generic group : CijcJopsina, 

 Milne-Edwards ('38); Glaucea, Koch ('38); and Ci/eJops, 

 Nicolet ('48). 



The first American species of Diaptomus recognizably 

 described was l>. saiif/itineus Forbes ('76). Later Dr. Forbes 

 ( '82a) described three additional species of this genus (sicllis, 

 Uptopus, and stagnalis), and two new genera of Centropagiche 

 {Episehura and Osphritniieuvi), with a single species of each. 

 Prof. C. L. Herrick's publications on the group began in 

 1877 and those of Marsh in 1891. A single species (D. 

 kentuchyensis) named by Chambers in 1881 is so imperfectly 

 described that its recognition is apparently impossible. Since 

 the publication of Underwood's " List of the described Species 

 of Fresh- water Crustacea from 2\.merica North of Mexico" 

 ('86) the number of recognized North American species of 

 Diaptomus has increased from five to twenty-three. 



The literature of the genus previous to 1889 was widely 

 scattered and the synonymy greatly complicated, but the 

 comprehensive and careful "Pievision" published in that 

 year by de Guerne and Eichard ('89b) has had the effect 

 greatly to facilitate its study. The most important recent 

 European contributions to a knowledge of the Centropayidce 



