XII CONTENTS. 



8. Organs of Secretion, 65 



9. Organs of Generation, 66-70 



rV. THE ECHINODERMATA. 



Classification and Bibliography, 71 



1. Cutaneous Envelope and Skeleton, 72-75 



2. Muscular System, and Organs of Locomotion, 76-78 



3. Nervous System, 79-80 



4. Organs of Sense, 81 



5. Digestive Apparatus, 82-86 



6. Circulatory System, 87-88 



7. Respiratory System, 89-93 



8. Organs of Secretion, 94 



9. Organs of Generation, 95-98 



V. THE HELMINTHES. 



Classification and Bibliography, 99 



1. Cutaneous System, 100-101 



2. Muscular System, and Organs of Locomotion, 102-103 



8. Nervous System, 104 



4. Organs of Sense, 105 



5. Digestive Apparatus, ." 106-109 



6. Circulatory System, 110-111 



7. Respiratory System, 112 



8. Organs of Secretion, 113 



9. Organs of Generation, 114-119 



VI. THE TUEBELLARIA. 



Classification and Bibliography, 120 



1. Cutaneous System, 121 



2. Muscular System, and Locomotive Organs, 122 



3, 4. Nervous System, and Organs of Sense, 123-124 



5. Digestive Apparatus, 125 



6, 7. Circulatory and Respiratory Systems, 126 



8. Organs of Secretion, 127 



9. Organs of Generation, 128-129 



Vn. THE ROTATORIA. 



Classification and Bibliography, 130 



1. Cutaneous System, 131 



2. Muscular System, and Locomotive Organs, 132-133 



3, 4. Nervous System, and Organs of Sense, 134-135 



5. Digestive Apparatus, 136 



6, 7. Circulatory and Respiratory Systems, 137-138 



8. Organs of Secretion, 139 



9. Organs of Generation, 140-141 



Vm. THE ANNELIDES. 



Classification and Bibliography 142 



1. Cutaneous System, 143 



2. Muscular System, and Locomotive Organs, 144-145 



