198 MANUAL OF ZOOLOGY. 



wanting ; but, as a rule, distinct branchiae are present. The 

 exact form and structure of the gills differ in different cases, 

 but their leading modifications will be alluded to in treating of 

 the different orders. 



TABULAR VIEW OF THE DIVISIONS OF THE CRUSTACEA. 



Sub-class I. EPIZOA (Haustellata). 

 Order i. Ichthyophthira. 



Sub-class II. CIRRIPEDIA. 



( Balanidae. 



Order 2. Thoracica. \ Vemicidse. 



( Lepadidse. 

 3. Abdominalia. 

 4. Apoda. 



Sub-class III. ENTOMOSTRACA. 



0rder S- ^ a ^, a - 

 6. Copepoda. 



7. Cladocera. 



8. Phyllopoda. Legion, Branchiopoda. 



9. Trilobita. 



10. Merostomata. 



Sub-class IV. MALACOSTRACA. 

 Division A. EDRIOPHTHALMATA. 



Order n. Lcemodipoda. 

 12. Isopoda. 

 13. Amphipoda. 

 Division B. PODOPHTHALMATA. 

 Order 14. Stomapoda. 

 15. Decapoda. 



Tribe a. Macrura. 

 b. Anomura. 

 c. Brachyura. 



CHAPTER XXXII. 

 EPIZOA AND CIRRIPEDIA. 



SUB-CLASS I. EPIZOA. (Haustellata). The members of this sub- 

 class of the Crustacea are in the adult state parasitic upon the 

 bodies of fishes, and are usually deformed ; but in the young 



