84 ANNUAL REPORT. 



INTRODUCTION. 



ENTOMOSTRACA. 



The name was derived from two Greek words meaning insect and shell, by 

 Otho F. Muller, and applied by him in his " Entomostraca'' (i785) to the animals 

 which had hitherto been all comprised in I.innseus' genus Monoculus, named 

 from the supposition that they all possessed but one eye. The name '' Branchi- 

 podes'* was also proposed, find would have been appropriate enough, but Muller 

 supposed that the branchial appendages which suggested the name, were want- 

 ing in Cythere, etc. Muller, aside from naming the group, was the first to 

 arrange these animals in anything like a systematic classification, and collected a 

 great deal of interesting mformation. Since his time several authors have writ- 

 ten upon these interesting animals in Europe, but with a few exceptions no sys- 

 tematic work on Entomostraca has appeared in English. 



Dr. W. Baird published in 1850 a superb work on the Entomostraca of Great 

 Britain, which is still the best thing in the English language. But smce ihis 

 woik was published, many additions have been made to our knowledge. In 

 Prof. J. D. Dana's magnificent work on the Crustacea found in the "Wilkes 

 Exploring Expedition", many new species are described, and a revised classifica- 

 tion lor the whole order is proposed. In this work every known genus was char- 

 acterized. Since then additions of new species have been published by various 

 authors, and are scattered through the reports of various societies. Moreover, 

 recent studies in Embryology have thrown new light on the classification of all 

 the lower animals, and many changes are necessary, but it is not possible at this 

 stage of the study to attempt a 



SYSTEMATIC AKRANGEMENT 



of this order. We shall follow quite closely Dana's system as being most com- 

 plete. 



The following changes, which will not affect essentially the nomenclature used 

 must be indicated as the necessary result of modem research : 



1. The Merostomata, or King Crab group, which contains the modem genus 

 Limulus (Horseshoe Crab) and the ancient Eurypteridce, etc., which was con- 

 sidered by Dana a sub-order of Entomostraca has by recent writers been regarded 

 as a distinct order intermediate between the Trilobita (which Dana included 

 with the sub-classes Chorestopoda and Entromostraca in the class Edriophtlialmia 

 or Tetradecapoda) and the Entomostraca. 



Trilobita now stands at the foot of the sub-kingdom, its inferiority in rank 

 being assumed from the inferiority in point of time. 



The Cormostomata (including Pa^cilopoda or Epizoa) has been united with 

 Copepoda (Cyclopacea) thus doing away with the sub-orders in Entomostraca. 



