22 LABORATORY DIRECTIONS 



48. (47) With ten or more pairs of trunk appendages 



SUBCLASS PHYLLOPODA, ORDER BRANCHIOPODA 



49 (46) Bivalve shell covering only part of body and fre- 

 quently ending posteriorly in a pointed spine. Head not en- 

 closed in the shell and bearing large, fringed antennae used in 

 swimming SUBCLASS PHYLLOPODA, ORDER CLADOCERA 



50 (45) Body covering firm and "sell-like" but not a hinged, 

 independent continuous shell covering the body 51 



51. (58) Eyes paired .....52 



52 (57) Head, thorax and abdomen all bearing appendages. 



SUBCLASS MALACOSTRACA 53 



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 later- 

 ally ~ ORDER AMPHIPODA 



57 (52) Abdomen lacking appendages; carapace lacking; 

 appendages 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. 

 Without rayed fins CLASS REPTILIA 



