INDEX AND GLOSSARY. 



Abd6men, 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, 23. 



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 Nature, 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 spelseus, 55. 



Ammonites, 22, 230, 232, 233. 



Amnios, 150. 



Amphibia, 95. 



Amphipods, a family of crusta- 

 ceans. 



Amphioxus. its place 181. 



Amphiuma, 209. 



Analogy, 30. 



Ana Ufa, 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, difference* be 



tween, 41. 

 Animate, possessed of animal life, 



43. 



Anoplotherium, 234. 

 Antenna, the jointed feelers ol 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. 

 Asteridae, the family of star-fishes, 



23. 

 Auditory, pertaining to the sense 



of hearing, 56. 

 Auricle, a cavity of the heart, like 



a little ear, 115. 

 Avicula decussata, 224. 

 Axolotl, 209. 



Baculites, 232. 



