28 ZOOLO GY DIEECTIONS 



53 (54) Eyes on the end of a movable stalk. Head and thorax 



fused and covered on sides and dorsal surface by a single 

 shell, the carapace. Five pairs of walking legs 



ORDER DECAPODA 



54 (53) Eyes not stalked 55 



55 (56) Body dorso-ventrally flattened order isopoda 



56 (55) Body almost cylindrical or compressed laterally 



order amphipoda 



57 (52) Abdomen lacking appendages; carapace lacking; ap- 



pendages flat, leaf -like 



SUBCLASS PHYLLOPODA, ORDER BRANCHIOPODA 



58 (51) A single eye in front of the head subclass copepoda 



VIII. PHYLUM CHORDATA 



SUBPHYLUM VeRTEBRATA 



1 (4) Body covered with scales or plates, (except in fishes 



with smooth skin) with or without rayed fins 2 



2 (3) Scales or plates dry and hard. Breathe by lungs. With- 



out rayed fins class reptilia 



3 (2) Scales or plates moist (rarely absent, in these cases dis- 



tinguishable by presence of rayed fins). Rayed fins always 

 present. Breathe by gills class pisces 



4 (1) Body not covered with scales 5 



5 (6) Cold blooded, skin slimy class amphibia 



6 (5) Warm blooded 7 



7 (8) Body covered with feathers class aves 



8 (7) Body covered with hair class mammalia 



references 

 Alexander, C. P., 1925. An Entomological Survey of the Salt 



Fork of the Vermilion River in 1921, with a Bibliography 



of Aquatic Insects, 111. Nat. Hist. Survey Bull., 15 



(art. 8). 

 Lutz, Frank E., 1921. Field Book of Insects. Revised. G. P. 



Putnam's Sons. 

 Ward, Henry B. and Whipple, George C, 1918. Fresh Water 



Biology. John Wiley and Sons, Inc. 



