INDEX. 



AARDVARK, 502. 



Aardwolf, 538. 



Abdominalia (Cirripedia), 198 ; characters 



of, 203 ; (Fishes), 361. 

 Abranchiata (Vertebrata), 337. 

 Abyla, 91. 

 Acalephce, 95, 99. 

 Acanthocephala, 158, 165; characters of, 



168, 169. 



Acanthometrina, 58. 

 Acanthopteri, 363. 

 Acanthopterygii, 358. 

 Acanthospongia, 64. 

 Acarida, 226. 

 Acarina, 224; characters and families of, 



225, 226. 



Accipitrince, 465, 466. 

 Acephala (Mollusca), 278. 

 Acerotherium, 565. 

 Acervulina, 53. 

 Acetabula, 299, 300. 

 Achetina, 244. 

 Achtheres, 199. 

 Acicula, 297. 

 Acwulidce, 294, 297. 

 Acineta, 71. 

 Acipenser, 378. 

 ,4cmoea, 295. 

 Acorn-Shells, 200, 201. 

 .Acrodlws, 373. 

 uimrtreta, 275. 

 Acteonm, 296. 

 Actinia, 110, 112, 113, 127. 

 Actinidce, 111-113; development of, 113. 

 Actinomeres, 125. 

 Actinophrys, 49, 50, 51. 

 Actinosoma, 111. 

 Actinozoa, 76; general characters of, 109- 



111; divisions of, 111; distribution of, 



129-133. 

 Acnleus, 249. 

 Adelarthrosomala, 224 ; characters and 



families of, 226, 227. 

 JEginida}* 98. 

 jEginnpsis, 98. 

 jKoliddK, 292, 296. 

 ^olis, 296. 

 jEpiornis, 470. 

 Agapornis, 458. 

 Agathistega, 54. 

 Agelacrinites, 151. 

 Ailurus, 535. 

 Air-bladder of Fishes, 351. 

 Air-receptacles of Birds, 436, 437. 



Alcedo, 463. 



Alca, 445. 



Alces, 523. 



^IZcwte, 445. 



Alcyonaria, 111; characters and divisions 

 of, 119, 120 ; distribution of in time, 133. 



Alcyonidce, 120. 



Alcyonium, 120. 



Allantoidea, 337. 



Allantois, 337, 338. 



Alligator, 414. 



Alpaca, 521. 



Alveolus (Belemnite), 306, 307. 



Amber, Insects preserved in, 252. 



Amblyrliynchus, 413. 



Ambulacral system (Echinodermata), 137; 

 of Echinus, 141 ; of Star-fishes, 145; of 

 Ophiuroidea, 147 ; of Crinoidea, 151 ; 

 of Holothuroidea, 153, 154. 



Ameivce, 411. 



Ametabolic Insects, 239, 241, 242. 



Ammodytes, 362. 



Ammonites, 310, 311, 312, 314. 



Ammonitidce, 309, 312; characters of, 

 310 ; distribution of, in time, 314. 



Amnion, 337. 



Amniota, 337. 



Amoeba, 6, 46; structure of, 47, 48; re- 

 production of, 48. 



Amoebea, 47, 49, 50. 



Amoebina, 50. 



Amphibia, 337, 375; general characters 

 of, 381, 383 ; development of, 381 ; re- 

 spiratory organs of, 382 ; orders of, 384; 

 distribution of, in time, 392. 



Amphiccelia (Crocodilia), 414, 415. 



Amphidiscs, 62, 63. 



Amphilestes, 560. 



Amphwxus, 326, 351, 353. 



Amphipneusta, 385. 



Amphipoda, 198; characters of, 212. 



Amphisbcenidce, 409. 



Amphispongia, 64. 



Amphitherium, 560, 561. 



Amphiuma, 385, 386. 



Ampullaria, 288, 295. 



Anacanthini, 362. 



Anallantoidea, 337. 



Anamniota, 337. 



Analogy, 16. 



Anarchropoda, 177. 



Anatidce, 447. 



Anatina, 285. 



Anatinidce, 284, 285. 



