Classification of the Crustacea. 4^69 



results an alteration in the classification of the Crustacea 

 in general. The group Entomostraca should be dissolved, and 

 a number of groups formed from it, which are to be considered 

 as equivalent to the Malacostraca. One of these natural 

 divisions is formed by the Euphyllopods in conjunction with 

 the Cladocera ; the Ostracoda are to be regarded as a second 

 special group of equal value, which has arisen from the 

 Estheria-iy^Q. The Copepoda and Cirripedia admit of being 

 combined in a third group, which may be designated Apodi- 

 formes. In accordance with this the Ostracoda may be termed 

 Esther ioeformes — a group, however, into which the Cladocera 

 cannot be received, on account of their separate origin from 

 the Esiheria-^^x'xQ.'s, \ the Cladocera must remain united with 

 the Euphyllopods, since they are derived from Estherid« of 

 the recent type. A fourth large natural group, which can be 

 traced back to the Branchipus-&Q\-\.Q?>, is constituted by the 

 Malacostraca. In conformity with the designations previously 

 chosen, this group also might be named Branchipodiformes. 



The classificatory system of the Crustacea would conse- 

 quently assume the following shape : — 



Class CRUSTACEA. 



Subclass I. PHYLLOPODA. 



Order 1. Euphyllopoda. 

 2. Cladocera, 



Subclass II. ESTHERI^FORMES. 



Order Ostracoda. 



Subclass III. APODIFORMES. 



Order 1. Copepoda. 

 2. Cirripedia. 



Subclass IV. MALACOSTRACA (Branchipodiformes). 

 I. Leptostraca. 

 Order Nebaliadce. 



II. EUMALACOSTRACA. 



Order 1. Stomatopoda. 



2. Thoracostraca. 



3. Arthrostraca. 



