2 26 APPENDIX 



Division i. Entomostraca. Small, simply constructed crustaceans with a 

 variable number of body segments and without abdominal appendages. 



Order i. Phyllopoda. Entomostracans with flat, leaflike appendages. 



Suborder i. Branchiopoda. Elongated phyllopods with segmented body. 

 Ex. Branchipus. 



Suborder 2, Cladocera. Laterally compressed phyllopods, the body 

 of which is not distinctly segmented and is inclosed in a bivalve shell ; sec- 

 ond pair of antennai are swimming organs and project from the shell. 

 Ex. Daphnia. 



Order 2. Copepoda. Elongated entomostracans with distinctly seg- 

 mented body and without gills ; the female often carries one or two egg sacs. 

 Ex. Cyclops. 



Order 3. Ostracoda. Minute, laterally compressed entomostracans with 

 entire body inclosed in a bivalve shell. Ex. Cypris. 



Order 4. Cirripedia. Sessile, hermaphroditic entomostracans with body 

 inclosed in a calcareous shell ; barnacles. Ex. Lepas. 



Division 2. Malacostraca. Crustaceans with a constant number (twenty) 

 of body segments and nineteen pairs of appendages; abdominal append- 

 ages present. 



Subdivision i. Phyllocarida. Primitive malacostracans with carapace 

 and with leaf like thoracic feet. Ex. Nebalia. 



Subdivision 2. Arthrostraca. Malacostracans with usually seven free 

 thoracic body segments, and with sessile eyes. 



Order i. Amphipoda. Laterally compressed arthrostracans with gills on 

 thorax. Ex. Gammarus. 



Order 2. Isopoda. Dorsoventrally depressed arthrostracans with gills 

 on the abdomen. Ex. Oniscus. 



Subdivision 3. Thoracostraca. Malacostracans with carapace covering 

 the head and all or some of the thorax, and with stalked eyes. 



Order i. Schizopoda. Small thoracostracans with carapace covering en- 

 tire thorax, and with one pair of maxillipeds. Ex. Mysis. 



Order 2. Stomatopoda. Thoracostracans with three free thoracic body 

 segments and large abdomen. Ex. Squilla. 



Order 3. Cumacea. Small thoracostracans with reduced carapace. Ex. 

 DiastyHs. 



Order 4. Decapoda. Large thoracostracans with carapace covering 

 entire thorax, and with three pairs of maxillipeds. 



Suborder i. Macrura. Elongated decapods with large abdomen. Ex. 

 Homarus. 



Suborder 2. Brachyura. Broad decapods with reduced abdomen. Ex. 

 Cancer. 



Class 2. Arachnoid ea. Arthropods lacking antennae and with body 

 usually consisting of cephalothorax and abdomen. 



