CONTENTS. 



PAGE 



PROTOZOA, . . l 



SPONGES, 39 



HYDROZOA, . 57 



PLANARIANS, 77 



NEMERTINES, . 83 



ROTIFERA, . 89 



MOLLUSCA, . . 95 



POLYZOA, . 169 



VERTEBRATA, . l73 



TUNICATA, ..... 185 



