STATE GEOLOGIST. 125 



All copepods, even such as are, in later life, parasitic, begin their 

 existence as free-swimmg nauplii, such as are represented on plate 

 S, fig. 13, and plate K, fig. 8. 



Though the vast majority of genera and species are marine, it 

 would seem that fresh-water copepods make up in the number of 

 individuals what they lack in variety. 



As we are dealing primarily with the fresh-water species, no 

 lengthy description of the group is here necessary. 



The earlier history of our knowledge of the animals of this order 

 is given by Baird. According to this authority, the first to mention 

 any fresh-water species of this group was Stephan Blanhaart ^ in his 

 SchotC'biirg cler Rupsen, Wormen^ Ma'clen, en vliegende DieJcens tot 

 Amsterdam. Leeuivenhoeh adds numerous interesting details and 

 is accredited by Hoek with being to first to discover the relation 

 between the remarkably diverse stages which occur in the history 

 of the Cyclops. However, it is evident that he had a very incomplete 

 knowledge of the metamophoses. 



De Geer gives rather characteristic figures of acyclops in Memoi- 

 res pour servir a VHistoire des Insectes, vol. vii, 1778. 



Mueller, in his great work on Entomostraca, adds new facts, 

 defines species and forms the genus Cyclops. 



Ra^ndohr in 1805 gave sundry additions to the knowledge of 

 these animals in his Beitraege zur Naturgesckichte einiger Deutschen 

 Monocidus-arten. In this work the post-embryonic history is quite 

 fully outlined. 



Jii7'ine, in his classic work Histoire des Monocles qui se trouvent 

 aux Envirous de Geneve, 1820, crystallized what previous authors 

 as well as his own original experiments had brought to light of the 

 anatomy and biology of these animals. 



Ferussac (Memoire sur deux novelles espices d'Entomostraces) 

 redescribes known species. 



Gunner, Stroem, and Viviana, seem to have had little effect on 

 the knowledge of the group, though they wrote prior to Juriue. 



A recent author attempts to revive the names of Jurine, though 

 hitherto it has been thought hazardous to attempt a specific identifi- 

 cation. 



The German author, C. L. Koch, who only incidentally studied 

 this group, distinguished more or less perfectly, a variety of species 

 which have been reinstated in our literature by Rehberg, Although 



1 T,atinized Stephanua Blanchardus . Hoek recognized Cyclops brevicaudatus orC. 

 bieuspidatus as the one described, chiefly through knowledge of the present inhabitants of 

 the locality . 



