INDEX AND GLOSSARY. 



Abdomen, the lower cavity of the 

 body, 17. 



Abranclaates, without gills, xvii. 



Acalepha, a class of Radiates many 

 species of which produce tingling 

 when handled. 



Acephala, mollusks having no dis- 

 tinct head, like clams, xix. 



Acoustic, pertaining to the sense of 

 hearing, 32. 



Actinia, digestive apparatus of, 73. 



Affinity, relationship, 6, 63. 



Ages of Nature, 189. 



Albumen, the white of egg, 108. 



Alimentary canal, 73. 



Alimentation, the process of nutri- 

 tion, 18. 



Allantois, Allantoidian, 119. 



Alligator, teeth of, 80. 



Alternate reproduction, 127 ; conse- 

 quences of, 136 ; difference be- 

 tween, and metamorphosis, 137. 



Amblyopsis spelaeus, 31. 



Ammonites, xvii. 198, 200, 201. 



Amnios, 120. 



Amphibia, 71. 



Amphipods, a family of crustaceans. 



Amphioxus, its place, 148. 



Amphiuma, 177. 



Analogy, 6. 



Anatifa, metamorphoses of, 145. 



Ancyloceras, 200. 



Animalcule, a minute animal, xix. 



Animal heat, 96. 



Animal life, 20 ; organs of, 20. 



Animals, number of, 3. 



Animals and plants, differences be- 

 tween, 17. 



18* 



Animate, possessed of conscious- 

 ness, 19. 



Anoplotherium, 202. 



Antenna, the jointed feelers of lob- 

 sters, insects, &c., 53. 



Aorta, the great blood-vessel arising 

 from the heart, 90. 



Aphides, reproduction of, 131. 



Apophysis, a projection from the 

 body of a bone, 149. 



Apparatus of motion, 48. 



Aptera, wingless insects, xvii. 



Aquatic, living in water. 



Aqueous, like water. 



Aqueous humor, 126. 



Arctic fauna, 164. 



Areolar tissue, 14. 



Arges, 193. 



Aristotle's lantern, 77. 



Arm, different forms of, 59. 



Artery, 90. 



Articulates, composed of joints, like 

 the lobster or caterpillar ; number 

 of, 3. 



Ascidia, bottle-shaped mollusks with- 

 out a shell. 



Assimilation, the change of blood in- 

 to bone, muscle, &c. 96. 



Astacus pellucidus, 31. 



Asteridee, the family of star-fishes, 

 xviii. 



Auditory, pertaining to the sense of 

 hearing, 32. 



Auricle, a cavity of the heart, like a 

 little ear, 89. 



Avicula decussata, 192. 



Axolotl, 177. 



