INDEX AND GLOSSARY. 



Abdomen, the lower cavity of the 

 body, 41. 



Abranchiates, without gills, 21. 



Acalepha, a class of Radiates, many 

 species of which produce tingling 

 of the skin when handled, 23T 



Acephala, mollusks having no dis- 

 tinct head, like clams, 22. 



Acoustic, pertaining to the sense of 

 hearing, 56. 



Actinia, digestive apparatus of, 97- 



Actinoids, 23. 



Affinity, relationship, 30, 87. 



Ages of Natnre, 221. 



Albumen, the white of egg, 42 ; 111, 

 138. 



Alimentary canal, 97. 



Alimentation, the process of nutri- 

 tion, 42. 



Allantois, Allantoidian, 149. 



Alligator, teeth of, 105. 



Alternate reproduction, 159 ; con- 

 sequences of, 167 ; difference be- 

 tween, and metamorphosis, 167. 



Ambling, 



91. 



Amblyopsis spelreus, 55. 



Ammonites, 22, 230, 232, 233. 



Amnios, 150. 



Amphibia, 95. 



Amphipods, a family of crusta- 

 ceans. 



Amphioxus, its place, 181. 



Amphiuma, 209. 



Analogy, 30. 



Anatifa, metamorphoses of, 177. 



Ancyl6ceras, 232. 



Animalcule, a minute animal, 24. 



Animal heat, 122. 



Animal life, 44 ; organs of, 44. 



Animals, number of, 27 ; distribu- 

 tion in space, 186 ; in time, 214. 



21 



Animals and plants, differences be- 

 tween, 41. 



Animate, possessed of animal life, 

 43. 



Anoplotherium, 234. 



Antenna, the jointed feelers of lob- 

 sters, insects, &c., 77. 



Aorta, the great bloodvessel arising 

 from the heart. 116. 



Aphides, reproduction of, 162, 163. 



Apophysis, a projection from the 

 body of a bone, 181. 



Apparatus of motion, 73. 



Aptera, wingless insects, 21. 



Aquatic, living in water. 



Aqueous, like water. 



Aqueous humor, 50. 



Arctic fauna, 197. 



Areolar tissue, 38. 



Arges, 225 



Aristotle's lantern, 102. 



Arm, 82 ; different forms of, 83. 



Artery, 113. 



Articulates, composed of joints, like 

 the lobster or caterpillar, 21 : 

 number of, 27. 



Ascidia, bottle-shaped mollusks 

 without a shell. 



Assimilation, the change of blood 

 into bone, muscle, &c., 122. 



Astacus pellucidus, 55. 



Asteridse, the family of star-fishes, 

 23. 



Auditory, pertaining to the sense 

 of hearing, 56. 



Auricle, a cavity of the heart, lile 

 a little ear, 115. 



Avicula decussata, 224. 



Axolotl, 209. 



Baculites, 232. 



